Gemstone Enhancement and Care


Gemstones have been enhanced through various methods for hundreds of years. Even the prettiest stones can come out of the ground looking like average rocks, but with a lapidary's skillful cutting and, sometimes, the application of enhancements like simple heat or more advanced procedures, their beauty is revealed.


While some stones like peridot and various garnets are usually not enhanced, many others are sometimes, regularly, or even always enhanced. Those enhancements are common, accepted, and even expected in the industry. Enhancements also help determine how to best care for your gemstones. The chart below lists our gemstones with the known possible enhancement methods for each stone.


Simply select the first letter of the gemstone you'd like to learn more about from the navigation below.


Also View:

Gemstone Enhancement Definitions

Gemstone and Jewelry Glossary




Abalone (shell)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
Abalone (shell) 3 no treatment n/a n/a n/a Shell is very soft so be mindful of scratching. Avoid sudden temperature changes, heat, chemicals, and ultrasonic cheaners. In addition to above precautions: avoid perfumes and hairsprays.  
3 dyed to add color commonly good DYED
3 stabilized prevent porosity occasionally fair STB
3 coated to protect and improve stability commonly good CTD
Agate (quartz)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
agate (quartz) 6.5 no treatment n/a n/a n/a Normal Care  
6.5 bleached to alter color commonly good to excellentBL
6.5 dyed n/a n/a n/a Avoid ultrasonics, heat, harsh cleanersDYED
Alexandrite (chrysoberyl)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
alexandrite (chrysoberyl) 8.5 not known to be treated n/a n/a n/a Normal Care  
8.5 oiled to improve clarity occasionally good Avoid ultrasonics, heat, harsh cleanersO
alexandrite, synthetic 8.5 lab created n/a n/a n/a Normal Care  
Almandite Garnet
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
almandite garnet 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
Amazonite (microcline feldspar)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
amazonite (microcline feldspar) 6.5 no treatment n/a n/a n/a Avoid hard wear, heat, chemicals and ultrasonic cleaners. 
6.5 heated to improve color occasionally very goodHE
6.5 dyed to improve color occasionally very goodDYED
6.5 impregnated with colorless wax or oil to improve overall appearance and luster occasionally good to fairIMP
6.5 impregnated with hardening agents or plastic to improve appearance and durability usually very goodIMP
Amber/Copal
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
amber / copal yellow, golden brown 2 - 2.5 no treatment n/a n/a n/a Amber is very soft, so be mindful of scratching. Copal is very soft and less stable than amber when left untreated. Avoid abrasives, ultrasonic, solvents and heat. Avoid prolonged direct sunlight, avoid alcohol and perfumes. Requires gentle handling. Clean with soft damp cloth only.  
2 - 2.5 heated to create sun spangles to improve appearance, deepen color, add spangles frequently good to very good HE
2 - 2.5 heated to improve clarity and darken color frequently very good HE
2 - 2.5 dyed/stained to alter color rarely variable DYED
2 - 2.5 pressed to create color, clarify and make gem larger commonly very good PRS
amber / copal green 2 - 2.5 blacken bottom of cab to create green color face up occasionally excellent Amber is very soft, so be mindful of scratching. Copal is very soft and less stable than amber when left untreated. Avoid abrasives, ultrasonic, solvents and heat. Avoid prolonged direct sunlight, avoid alcohol and perfumes. Requires gentle handling. Clean with soft damp cloth only.BLKND
2 - 2.5 heat and pressure in an autoclave to create color and mature copals frequently excellentLPLT
2 - 2.5 dyed to create color frequently good to very goodDYED
2 - 2.5 pressed and dyed to create color, and a larger gem frequently excellentPRS
amber / copal red 2 - 2.5 heated to create color frequently good to very good Amber is very soft, so be mindful of scratching. Copal is very soft and less stable than amber when left untreated. Avoid abrasives, ultrasonic, solvents and heat. Avoid prolonged direct sunlight, avoid alcohol and perfumes. Requires gentle handling. Clean with soft damp cloth only.HE
  dyed to create color frequently good to very goodDYED
2 - 2.5 pressed and dyed to create color, and a larger gem frequently excellentPRS
amber / copal doublet - all colors 2 - 2.5 assembled to alter color occasionally good Amber is very soft, so be mindful of scratching. Copal is very soft and less stable than amber when left untreated. Avoid abrasives, ultrasonic, solvents and heat. Avoid prolonged direct sunlight, avoid alcohol and perfumes. Requires gentle handling. Clean with soft damp cloth only. AS
Amblygonite (montebrasite)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
amblygonite (montebrasite) 5.5 - 6 no treatment n/a n/a n/a Gentle wear, can be brittle. Avoid high temperatures. 
amblygonite (montebrasite) blue, green, yellow 5.5 - 6 irradiated to alter color frequently goodIRR
Amethyst
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
amethyst 7 no treatment n/a n/a n/a Normal Care 
7 heated to improve color commonly excellentHE
Ametrine
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
ametrine 7 no treatment n/a n/a n/a Normal Care 
7 heated to improve color occasionally excellentHE
Ammolite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
ammolite doublet 3.5 - 4 assembled to improve durability frequently fair to good Ammolite is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling. AS
ammolite triplet 6 assembled glass top to improve durability frequently good Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling. AS
ammolite triplet 7 assembled quartz top to improve durability frequently good AS
ammonite (fossil) 3.5 - 4 no treatment n/a n/a n/a Normal care  
Andalusite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
andalusite 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 heated to improve color occasionally excellent HE
chiastolite 5 - 5.5 no treatment n/a n/a n/a Normal Care 
viridine 7 - 7.5 no treatment n/a n/a n/a Normal Care 
Andesine-Labradorite (plagioclase feldspar)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
andesine-labradorite Red / Green / Orange (plagioclase feldspar) 6 - 6.5 no treatment n/a n/a n/a Normal Care 
6 - 6.5 diffused to alter color commonly excellentDIF
Andradite Garnet
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
andradite garnet 6.5 not known to be treated n/a n/a n/a Normal Care  
color change andradite garnet 6.5 no treatment n/a n/a n/a  
demantoid garnet (andradite) 6.5 no treatment n/a n/a n/a  
6.5 low temperature heat to improve color often excellent HE
rainbow andradite 6.5 no treatment n/a n/a n/a  
Apatite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
apatite
green
5 no treatment n/a n/a n/a Apatite is moderately soft, so be mindful of scratching. Avoid ultrasonic cleaners. 
apatite
blue
5 no treatment n/a n/a n/a  
apatite
blue and yellow
5 heated to improve color frequently good HE
5 irradiated to improve color occasionally goodIRR
cat's-eye, apatite 5 no treatment n/a n/a n/a Apatite is moderately soft, so be mindful of scratching. Avoid ultrasonic cleaners. 
5 heated to improve color frequently goodHE
Aquamarine (beryl)
aquamarine (beryl) 7.5 - 8 no treatment n/a n/a n/a Normal Care 
7.5 - 8 heated to improve color frequently excellentHE
Aragonite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
aragonite all colors 3.5 - 4 no treatment n/a n/a n/a Aragonite is very soft, so be mindful of scratching. It is easily attacked and dissolved by acids such as vinegar. Avoid abrasives, ultrasonic, solvents and heat. Aragonite is generally unsuitable for jewelry 
3.5 - 4 dyed to alter color sometimes fair to goodDYED
3.5 - 4 waxed to improve finish and durability sometimes fair to goodW
Aventurine (quartzite)
aventurine
(quartzite)
6.5 no treatment n/a n/a n/a Normal Care 
6.5 dyed to improve color commonly good to excellent Avoid abrasives, ultrasonic, solvents and heat.DYED
Axinite
axinite 6.5 - 7 no treatment n/a n/a n/a Normal gentle care, avoid sharp knocks to prevent cleavage. 
Azurite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
azurite 3.5 - 4 no treatment n/a n/a n/a Azurite is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Azurite is generally unsuitable for jewelry 
3.5 - 4 coated to improve appearance and durability occasionally fair to goodCTD
3.5 - 4 filled with oil/resin and polymer to stabilize & improve appearance occasionally goodO
azurite in granite 5 - 7 no treatment n/a n/a n/a Normal Care 
Azurmalachite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
azurmalachite 3.5 - 4 no treatment n/a n/a n/a Azurmalachite is very soft, so be mindful of scratching/breaking. Avoid abrasives, ultrasonic, solvents and heat. 
3.5 - 4 impregnated to improve appearance and durability rarely fair to goodIMP
3.5 - 4 filled with oil/resin and polymer to improve appearance and durability rarely goodO


Bastnasite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
bastnasite 4 - 4.5 not known to be treated n/a n/a n/a Gentle wear, moderately soft and brittle. Not suitable for jewelry.
Benitoite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
benitoite 6.5 not known to be treated n/a n/a n/a Normal, gentle care. 
6.5 heated to improve color sometimes fair to goodHE
Beryl
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
aquamarine (beryl) 7.5 - 8 no treatment n/a n/a n/a Normal Care 
7.5 - 8 heated to improve color frequently excellentHE
bixbite, red (beryl) 7.5 - 8 oiled/resin infused to improve clarity frequently fair to good, may require maintenance Avoid ultrasonic cleaners, and harsh chemicals.O
7.5 - 8 ExCel™/hardened polymers to improve clarity and stability occasionally very good Normal CarePOLY
bixbite in rhyolite, Bayez Bixbite 7.5 - 8 no treatment n/a n/a n/a Normal Care 
goshenite, colorless beryl 7.5 - 8 not known to be treated n/a n/a n/a Normal Care 
green (beryl) 7.5 - 8 not known to be treated n/a n/a n/a Normal Care 
heliodor (yellow beryl) 7.5 - 8 irradiated to produce color almost always variable Normal Care, but some stones may fade in prolonged exposure to light or heat.IRR
emerald 7.5 - 8 no treatment n/a extremely rare n/a Normal Care 
7.5 - 8 oiled/resin infused to improve clarity frequently fair to good, may require maintenance Avoid extreme heat, steaming, chemicals and ultrasonic cleaners.O
7.5 - 8 Excel™/hardened polymers to improve clarity and stability occasionally very good Normal CarePOLY
7.5 - 8 dyed with colored polymers to improve color and clarity occasionally fair to good Avoid extreme heat, steaming, chemicals and ultrasonic cleaners. DYED
trapiche emerald 7.5 - 8 oiled/resin infused to improve clarity almost always fair to good, may require maintenance Avoid extreme heat, steaming, chemicals and ultrasonic cleaners.O
7.5 - 8 dyed/stained to alter color occasionally variable Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.DYED
maxixe blue (beryl) 7.5 - 8 irradiated to create the blue color always poor Maxixe beryl is very special. Avoid prolonged exposure to light and heat to avoid quick fading of color.IRR
morganite pink, peach (beryl) 7.5 - 8 no treatment n/a n/a n/a Normal Care 
7.5 - 8 heated to improve color frequently excellentHE
7.5 - 8 irradiated to produce color frequently excellentIRR
synthetic beryl, emerald, red beryl, aquamarine 7.5 - 8 lab created n/a n/a n/a Normal Care 
Bixbite (beryl)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
bixbite, red (beryl) 7.5 - 8 oiled/resin infused to improve clarity frequently fair to good, may require maintenance Avoid extreme heat, steaming, chemicals and ultrasonic cleaners.O
7.5 - 8 ExCel™/hardened polymers to improve clarity and stability occasionally very good Nomal CarePOLY
bixbite in rhyolite, Bayez Bixbite 7.5 - 8 no treatment n/a n/a n/a Normal Care 
Black Onyx (chalcedony)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
black onyx (chalcedony) 6.5 dyed/stained to alter color almost always fair to good Normal CareDYED
6.5 irradiated to darken color commonly excellent Nomal CareIRR
Blue Topaz
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
Blue Topaz - sky, swiss, london, super 8 irradiated and annealed to create color almost always excellent Normal CareIRR
8 CVD Coated to add color occasionally fair to good Avoid repolishing, scratching or abrading - color coating may be chipped or scratched off.CVD
Blue Moon Quartz
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
Blue Moon Quartz 7 heated to create effect always excellent Normal CareHE
Blueberry Quartz
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
Blueberry Quartz 7 irradiated /annealed to create color always excellent Normal CareIRR
Bone / Ivory
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
bone / ivory 2 - 3 no treatment n/a n/a n/a Requires gentle handling. Bone and ivory are very soft and may discolor with time. Be mindful of scratching. 
2 - 3 bleached to improve color commonly good Bone and ivory are very soft and may discolor with time. Discoloration is due to porosity/absorption of body oils or other substances from wearing. Be mindful of scratching. Avoid chemicals and ultrasonic cleaners. Requires gentle handlingBL
2 - 3 dyed/stained to alter color or to look aged often goodDYED
2 - 3 impregnated to minimize porosity occasionally goodIMP
mammoth (ivory) 2 - 3 impregnated / bleached to improve appearance and stability commonly good Mammoth ivory is very soft and may discolor with time. Discoloration is due to porosity/absorption of body oils or other substances from wearing. Be mindful of scratching Avoid chemicals and ultrasonic cleaners. Requires gentle handlingIMP
horn 2.5 no treatment n/a n/a n/a Horn is a soft, organic product. Avoid heat, chemicals and ultrasonic cleaners. Requires gentle handling. 
2.5 heated to shape often fairHE
shark teeth *** not known to be treated n/a n/a n/a Most shark teeth are actually fossils. Gentle Care. 
walrus tusk 2.5 no treatment n/a n/a n/a Walrus tusks are very soft and may discolor with time. Discoloration is due to porosity/absorption of body oils or other substances from wearing. Be mindful of scratching. Avoid chemicals and ultrasonic cleaners. Requires gentle handling 
2.5 bleached to even color, improve lustre often goodBL
2.5 stained to add color, appear aged often goodSTN
whale teeth 2.5 no treatment n/a n/a n/a Whale teeth are very soft and may discolor with time. Discoloration is due to porosity/absorption of body oils or other substances from wearing. Be mindful of scratching. Avoid chemicals and ultrasonic cleaners. Requires gentle handling 
2.5 bleached to even color, improve lustre often very goodBL
2.5 stained to add color, appear aged sometimes fair to goodSTN


Calcite - Marble
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
aragonite
all colors
3.5 - 4 no treatment n/a n/a n/a Aragonite is very soft, so be mindful of scratching. It is easily attacked and dissolved by acids such as vinegar. Avoid abrasives, ultrasonic, solvents and heat. Aragonite is generally unsuitable for jewelry.  
3.5 - 4 dyed to alter color occasionally fair to good DYED
3.5 - 4 waxed to improve finish and durability occasionally fair to good W
cats eye calcite 3 not known to be treated n/a n/a n/a Gentle care, very soft. Avoid ultrasonic cleaners, vinegar, harsh cleaners.  
marble 3 no treatment n/a n/a n/a Gentle care, moderately soft. Avoid ultrasonic cleaners, vinegar, harsh cleaners.  
3 dyed to add color frequently good to excellent Gentle care, moderately soft. Avoid ultrasonic cleaners, vinegar, harsh cleaners. DYED
3 lacquered to improve appearance and durability occasionally fair to good Gentle care, moderately soft. Avoid ultrasonic cleaners, vinegar, harsh cleaners. CTD
Cat's Eye Glass, fiber optic glass
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
cat's eye glass, fiber optic glass 5 - 6 man made n/a n/a n/a Normal Care  
Calsilica
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
calsilica 5 - 6 composite n/a n/a n/a Gentle Care COMP
Cavansite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
cavansite 3 - 4 no treatment n/a n/a n/a Gentle handling (specimen)  
Cerussite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
cerussite 3.5 not known to be treated n/a n/a n/a Very soft gentle care, not suitable for jewelry.  
Chalcedony (polycrystalline and microcrystaline quartz)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
agate(quartz) 6.5 no treatment n/a n/a n/a Normal Care  
6.5 bleached to alter color commonly good to excellent Normal Care BL
6.5 dyed n/a n/a n/a Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. DYED
blue chalcedony (quartz) 6.5 no treatment n/a n/a n/a Normal Care  
6.5 dyed to alter color commonly fair to good Avoid harsh chemicals, accetone and ultrasonic cleaners. Can be affected by perspiration. DYED
blue, green, paraiba color chalcedony (quartz) 6.5 no treatment n/a n/a n/a Normal Care  
6.5 irradiated to alter color occasionally fair to good Normal wear, but some stones may fade in light or heat. IRR
6.5 dyed/stained to alter color almost always poor to fair Avoid harsh chemicals, acetone and ultrasonic cleaners. Some stones may fade in light or heat. Can be affected by perspiration. DYED
banded agate (chalcedony) 6.5 no treatment n/a n/a n/a Normal Care  
6.5 dyed/stained to alter color commonly excellent DYED
black onyx (chalcedony) 6.5 dyed/stained to alter color almost always fair to good Normal Care DYED
6.5 irradiated to darken color commonly excellent IRR
bloodstone (chalcedony) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care  
carnelian / sard (chalcedony) 6.5 heated to improve color usually excellent Normal Care HE
6.5 dyed/stained to alter color often good to excellent Normal Care DYED
cat's eye, chalcedony 6.5 no treatment n/a n/a n/a Normal Care  
6.5 heated to alter color usually excellent HE
6.5 chemical bleaching with acid or bleaching agents to lighten color occasionally excellent BL
chrysocolla (chalcedony) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care  
6 - 6.5 dyed to improve color occasionally good to excellent Avoid harsh chemicals, acetone and ultrasonic cleaners. DYED
chrysoprase (chalcedony) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care  
6.5 heated to improve color occasionally excellent HE
dendritic agate (chalcedony) 6.5 not known to be treated n/a n/a n/a Normal Care  
dumortierite quartz 6.5 no treatment n/a n/a n/a Normal Care  
6.5 oiling to reduce appearance of natural fissures occasionally fair Avoid extreme heat, steaming, chemicals and ultrasonic cleaners. O
fire agate (chalcedony) 6.5 not known to be treated n/a n/a n/a Normal Care  
jasper (quartz) 6 - 6.5 no treatment n/a n/a n/a Normal Care  
6 - 6.5 dyed to add color occasionally fair to excellent Avoid chemicals, steam, and ultrasonic cleaners DYED
6 - 6.5 heated to improve color occasionally excellent Normal Care HE
jasper beads (quartz) 6 - 6.5 lacquered prevent porosity occasionally fair Avoid chemicals, steam, and ultrasonic cleaners.  
moss agate (quartz) 6.5 not known to be treated n/a n/a n/a Normal Care  
petrified wood (quartz) 6.5 no treatment n/a n/a n/a Normal Care  
6.5 bleached to remove color occasionally excellent BL
6.5 heated to improve color occasionally very good HE
pietersite, henanite 6.5 not known to be treated n/a n/a n/a Normal Care  
hawk's-eye, blue tiger's eye 6.5-7 no treatment n/a n/a n/a Normal Care  
6.5-7 chemical bleaching with acid or bleaching agents to lighten color occasionally excellent BL
tiger's-eye, brown 6.5 no treatment n/a n/a n/a Normal Care  
6.5 chemical bleaching with acid or bleaching agents to lighten color occasionally excellent BL
tiger's-eye, red 6.5 heated to change from gold to red usually excellent Normal Care HE
6.5 chemical bleaching with acid or bleaching agents to lighten color occasionally excellent BL
6.5 dyed to alter color occasionally very good Avoid sudden temperature changes, chemicals, steam and ultrasonic cleaners. DYED
Charoite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
charoite 5-6 no treatment n/a n/a n/a Normal Care  
5-6 impregnated to improve durability commonly good Avoid hot water, household chemicals, and ultrasonic cleaners IMP
Chrysoberyl
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
alexandrite (chrysoberyl) 8.5 not known to be treated n/a n/a n/a Normal Care  
8.5 oiled to improve clarity occasionally good avoid ultrasonics, heat, and harsh cleaners O
cat's-eye (chrysoberyl) 8.5 no treatment n/a n/a n/a Normal Care 
8.5 heated to improve color occasionally excellent Normal CareHE
brown, yellow, green (chrysoberyl) 8.5 no treatment n/a n/a n/a Normal Care 
8.5 irradiated to create color rarely excellent Normal CareIRR
8.5 heated to improve color occasionally excellent Normal CareHE
alexandrite, synthetic 8.5 lab created n/a n/a n/a Normal Care 
Chrysocolla
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
chrysocolla 2.5 – 3.5 no treatment n/a n/a n/a Chrysocolla is very soft, so be mindful of scratching. Requires gentle handling.  
chrysocolla chalcedony 6 – 6.5 not known to be treated n/a n/a n/a Normal care  
6 – 6.5 dyed to improve color occasionally good to excellent Avoid harsh chemicals, acetone and ultrasonic cleaners. DYED
Chrysoprase (chalcedony)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
chrysoprase(chalcedony) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care  
6.5 heated to improve color occasionally excellent HE
Cinnabar (lacquer)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
cinnabar (lacquer) 3 - 4 man made n/a n/a good Gentle wear, avoid ultrasonics and high heat. Modern cinnabar is safe and does not contain mercury.  
Citrine
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
citrine (all types) 7 no treatment n/a n/a n/a Avoid jewelers torches  
7 heated to alter color usually excellent HE
lemon quartz, lemon citrine, ouro verde quartz 7 irradiated to create color always excellent Normal Care IRR
Clinohumite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
clinohumite 6 not known to be treated n/a n/a n/a Requires gentle handling.
Coral
Please be assured that JTV goes to great lengths to comply with all laws protecting endangered species.
The term "polycoral" is used to describe products that are composed of coral fragments (and often other ocean products) which are then dyed and bonded with polymers.
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
bamboo / sponge (coral, polycoral) 3-4 no treatment n/a n/a n/a Normal, gentle care. Avoid ultrasonic cleaners, steam and extreme heat.  
3 - 4 impregnated with wax/oil/plastic to improve appearance and luster frequently good IMP
3 - 4 dyed/stained to alter colorr frequently good DYED
3 - 4 assembled and dyed to create coral effect and color from smaller stones frequently fair to good COMP
precious coral, branch coral 3 - 4 dyed/waxed to improve color and texture frequently good Normal, gentle care. Avoid ultrasonic cleaners, steam and extreme heat. DYED
3 - 4 impregnated with colorless wax or oil to improve the quality of material for shaping and polishing frequently goodIMP
3 - 4 impregnated with plastic to improve quality of material for shaping and reploshing frequently very goodIMP
3 - 4 assembled and dyed to create coral effect from smaller stones frequently fair to goodCOMP
black coral 3 - 4 no treatment n/a n/a n/a Normal, gentle care. Avoid ultrasonic cleaners, steam and extreme heat. 
3 - 4 waxed to improve overall appearance and luster frequently fair to goodW
golden coral 3 - 4 bleached to bring out color always excellent Normal, gentle care. Avoid ultrasonic cleaners, steam and extreme heat.BL
3 - 4 bleached and waxed to improve overall appearance and luster frequently fair to goodBL
Corundum
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
ruby (corundum) 9 no treatment(extremely rare) n/a n/a n/a Normal Care 
9 heated to improve colorand clarity usually excellentHE
9 infilled - glass or flux filled to improve color and clarity commonly good to excellentINF
9 Beryllium lattice diffusion to improve color occasionally excellent Avoid recutting, otherwise Normal CareBE DIF
6 - 9 lead glass filled (fissure filled)
See Hybrid
to improve clarity and color commonly poor Avoid common household chemicals, steam cleaners, and ultrasonic cleaners .Avoid jewelers torches.LGF
6 - 9 flux healed to improve clarity commonly excellent Normal careFH
9 surface diffusion to create asterism or color occasionally good Avoid repolishing / recutting and scratching.DIF
9 dyed/stained with colored oils or polymers to improve color and clarity occasionally poor Avoid harsh chemicals, heat and ultrasonic cleaners.DYED
ruby beads 9 waxed/oiled to improve clarity and luster frequently poor Avoid harsh chemicals, heat and ultrasonic cleaners.W
star ruby all (corundum) 9 no treatment n/a n/a n/a Avoid jewelers torches, otherwise Normal Care 
6 - 9 lead glass filled (fissure filled) SeeHybrid to improve clarity and color occasionally poor to fair Avoid common household chemicals, steam cleaners, and ultrasonic cleaners. Avoid jeweler's torches.LGF
9 surface diffusion to implant star occasionally excellent Avoid repolishing / recutting, scratching and jeweler's torches.DIF
9 heated to improve color sometimes excellent Avoid jewelers torches, otherwise Normal CareHE
sapphire, blue (corundum) 9 no treatment(rare) n/a n/a n/a Normal Care 
9 heated to improve color and clarity usually excellent Normal CareHE
9 dyed/stained with colored oils or polymers to improve color and clarity occasionally fair to good Avoid harsh chemicals, heat and ultrasonic cleaners.DYED
9 beryllium lattice diffusion to lighten color occasionally excellent Avoid recutting, otherwise Normal CareBE DIF
9 surface diffusion to create or improve color occasionally good Avoid chipping or repolishingDIF
6 - 9 lead glass filled (fissure filled) See Hybrid to add color and improve clarity sometimes fair to poor Avoid common household chemicals, steam cleaners, ultrasonic cleaners and a jewelers torch.LGF
sapphire, fancy (green, orange, purple, pink, padparadscha, yellow) (corundum) 9 no treatment n/a n/a n/a Normal Care 
9 heated to improve color and clarity usually excellent Normal CareHE
6 - 9 lead glass filled (fissure filled) See Hybrid to improve clarity and color occasionally poor Avoid common household chemicals, steam cleaners, ultrasonic cleaners, and jewelers torches.LGF
9 beryllium lattice diffusion to improve color commonly excellent Avoid recutting, otherwise Normal CareBE DIF
sapphire, star blue (corundum) 9 no treatment n/a n/a n/a Avoid jewelers torches, otherwise Normal Care 
9 heated improve color sometimes excellentHE
9 surface diffusion to implant star often excellent Avoid repolishing / recutting, scratching and jeweler's torches.DIF
6 - 9 lead glass filled (fissure filled) See Hybrid to improve clarity and color occasionally fair to poor Avoid common household chemicals, steam cleaners, and ultrasonic cleaners. Avoid jeweler's torches.LGF
sapphire, star gray - white (corundum) 9 no treatment n/a n/a n/a Avoid jewelers torches, otherwise Normal Care 
9 surface diffusion to implant star occasionally Excellent Avoid repolishing / recutting, scratching and jeweler's torches.DIF
sapphire, black star (corundum) 9 no treatment n/a n/a n/a Normal Care 
9 lacquered prevent flaking often fair Avoid harsh solvents and ultrasonic cleanersCTD
6 - 9 lead glass filled (fissure filled) See Hybrid reduce appearance of cracks commonly fair to poor Avoid common household chemicals, steam cleaners, and ultrasonic cleaners.LGF
Crystal (glass)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
crystal (glass) 6 man-made n/a n/a n/a Normal Gentle Care  
Cubic Zirconia
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
cubic zirconia 8 - 8.5 lab created n/a n/a n/a Normal Care 
8 - 8.5 CVD coated to add optic effects rarely poor to good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals. Coating can be scratched.CVD
Cuprite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
cuprite 5 - 6 no treatment n/a n/a n/a Gentle wear, avoid chemicals and ultrasonics  


Danburite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
danburite 7-7.5 not known to be treated n/a n/a n/a Normal Care  
Demantoid Garnet (andradite)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
demantoid garnet (andradite) 6.5 no treatment n/a n/a n/a Normal Care  
6.5 low temperature heat to improve color often excellent HE
Diamond
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
diamond normal color range D - Z 10 no treatment n/a n/a n/a Normal Care 
10 HPHT (high pressure,high temperature) to lighten or change color occasionally excellent Normal CareHPHT
10 lasered & bleached with acid to improve clarity often very good Normal Care LAS
10 fracture filled to improve clarity occasionally good to very good Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.In addition to the above precautions: Avoid jeweler's torch and recutting.FF
10 CVD coated to add or minimize color rarely poor to good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.CVD
diamond champagne 10 no treatment n/a n/a n/a Normal Care 
10 HPHT (high pressure,high temperature) to improve color occasionally excellent HPHT
diamond fancy color 10 no treatment n/a n/a n/a Normal Care 
10 HPHT (high pressure,high temperature) to improve color occasional/increasingly common excellent Normal CareHPHT
10 HPHT and irradiated to improve color occasional/increasingly common excellentHPHT
10 lasered & filled to improve clarity occasionally very good Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners. addition to the above precautions: Avoid jeweler's torch and recutting.LAS
10 irradiated to create color often very good to excellent Normal CareIRR
10 fracture filled to improve clarity sometimes good to very good Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.In addition to the above precautions: Avoid jeweler's torch and recutting.FF
10 CVD coated to add color sometimes poor to good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.CVD
diamond black 10 no treatment n/a n/a n/a Normal Care 
10 irradiated to intensify color often very good to excellent IRR
Diaspore
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
diaspore
zultanite™
6.5 - 7 not known to be treated n/a n/a n/a Cleaves easily, or is known to brittleness. Avoid ultrasonic cleaners. Wear with care. 
cat's eye diaspore
zultanite™
6.5 - 7 oiled to improve appearance commonly fair Cleaves easily, or is prone to brittleness. Avoid ultrasonic cleaners, heat and chemicals. Wear with care.O
Diopside
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
chrome diopside 5.5 not known to be treated n/a n/a n/a Diopside is moderately soft, so be mindful of scratching. Avoid abrasives and solvents.
black star (diopside) 5.5 not known to be treated n/a n/a n/a
Shanseres (diopside) 5.5 not known to be treated n/a n/a n/a
Dolomite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
dolomite 3.5 - 4 waxed/lacquered to improve finish and durability frequently fair Normal, gentle care.CTD
dolomite (laguna lace agate) 3.5 - 4 dyed to add colors frequently goodgentle care, avoid heat and harsh chemicalsDYED
Drusy Quartz
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
drusy quartz 7 no treatment n/a n/a n/a Normal care 
7 coated to create color or iridescence often good Gentle care. Avoid abrasions that can remove or scratch coating.CTD
7 CVD to produce color frequently very good Chipping may reveal natural color, so avoid abrasions. Cannot be re-cut or re-polished. Avoid heat, chemicals, and ultrasonic cleaners.CVD
7 heated to improve color occasionally excellent Normal careHE


Eilat Stone
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
eilat stone 4 - 6 waxed to improve finish and durability frequently fair - good gentle care, avoid heat and harsh chemicals W
Emerald
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
emerald 7.5 - 8 no treatment n/a extremely rare n/a Normal Care 
7.5 - 8 oiled/resin infused to improve clarity frequently fair to good, may require maintenance Avoid extreme heat, steaming, chemicals and ultrasonic cleaners.O
7.5 - 8 Excel™/hardened polymers to improve clarity and stability occasionally very good Normal CarePOLY
7.5 - 8 dyed with colored polymers to improve color and clarity occasionally fair to good Avoid extreme heat, steaming, chemicals and ultrasonic cleaners. DYED
trapiche emerald 7.5 - 8 oiled/resin infused to improve clarity almost always fair to good, may require maintenance Avoid extreme heat, steaming, chemicals and ultrasonic cleaners. O
7.5 - 8 dyed/stained to alter color occasionally variable Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners. DYED
emerald, synthetic 8 lab created n/a n/a n/a Normal Care  
Enstatite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
enstatite 5.5 not known to be treated n/a n/a n/a Moderately soft, so be mindful of scratching. Requires gentle handling.
hypersthene 5-6 not known to be treated n/a n/a n/a
Euclase
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
euclase 7.5 not known to be treated n/a n/a n/a Cleaves easily, or is prone to brittleness. Avoid ultrasonic cleaners.Wear with care.
Eudialyte
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
eudialyte 5 - 6 not known to be treated n/a n/a n/a Moderately soft and brittle, so be mindful of sratching.


Feldspar
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
amazonite (microcline feldspar) 6.5 no treatment n/a n/a n/a Avoid hard wear, heat, chemicals and ultrasonic cleaners. 
6.5 heated to improve color occasionally very goodHE
6.5 dyed to improve color occasionally very goodDYED
6.5 impregnated with colorless wax or oil to improve overall appearance and luster occasionally good to fairIMP
6.5 impregnated with hardening agents or plastic to improve appearance and durability usually very goodIMP
moonstone, adularia (orthoclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care 
orthoclase, various colors 6 - 6.5 not known to be treated n/a n/a n/a Normal Care 
sunstone (orthoclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid ultrasonic cleaners. 
albite (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care 
andesine-labradorite Red / Green / Orange (plagioclase feldspar) 6 - 6.5 no treatment n/a n/a n/a Normal Care 
6 - 6.5 diffused to alter color commonly excellent Normal CareDIF
labradorite (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling 
6 - 6.5 oiled to improve appearance occasionally fair to good Avoid ultrasonic cleanersO
labradorite yellow (plagioclase feldspar) 6 - 6.5 no treatment n/a n/a n/a Normal, gentle handling 
6 - 6.5 irradiated to improve color commonly good Normal, gentle handling. Avoid heat.IRR
6 - 6.5 CVD coated to add color occasionally fair to good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.CVD
Larvikite - Gabbro (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. 
6 - 6.5 waxed to improve appearance occasionally fair to good Avoid ultrasonic cleanersW
sunstone (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid ultrasonic cleaners. 
6 - 6.5 oiled to improve appearance occasionally fair to good Avoid ultrasonic cleaners. O
Fluorite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
fluorite 4 no treatment n/a n/a n/a Very soft stone, requires gentle handling. Color can be reversed with heat - avoid heat and jeweler torches. 
4 heated to improve color occasionally fair to goodHE
4 irradiated to alter/improve color frequently fair to goodIRR
Forsterite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
forsterite 7 lab created n/a n/a n/a Normal care 
Fossils
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
trilobites 3 - 4 not known to be treated n/a n/a n/a Normal, gentle care care  
fossil coral 3 - 4 no treatment n/a n/a n/a  
ammonite (fossil) 3 - 4 no treatment n/a n/a n/a  
shark teeth *** not known to be treated n/a n/a n/a Most shark teeth are actually fossils. Gentle Care. 


Garnet
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
almandite garnet 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
andradite garnet 6.5 not known to be treated n/a n/a n/a Normal Care 
anthill garnet (chrome pyrope) 7 not known to be treated n/a n/a n/a Normal Care 
color change garnet 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
color change andradite 6.5 no treatment n/a n/a n/a Normal Care 
demantoid (andradite) 6.5 no treatment n/a n/a n/a Normal Care 
6.5 low temperature heat to improve color often excellentHE
hessonite / imperial (grossular) 7 not known to be treated n/a n/a n/a Normal Care 
hyderabad 7 not known to be treated n/a n/a n/a Normal Care 
malaya garnet, malaia 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
Mali (grossular-andradite) 6.5 - 7 not known to be treated n/a n/a n/a Normal Care 
Masasi™ Bordeaux Garnet (almandine, spessartite, grossular) 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
Merelani mint garnet (grossular) 7 not known to be treated n/a n/a n/a Normal Care 
Mozambique 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
pyrope 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
rainbow andradite 6.5 no treatment n/a n/a n/a Normal Care 
rhodolite 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
spessartite 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
Sunset Native™ Garnet (almandine, pyrope, grossular, and spessartine) 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
Tanga™ (almandite/pyrope) 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
tsavorite (grossular) 7 not known to be treated n/a n/a n/a Normal Care 
umbalite, malaya, malaia 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
uvarovite 6.5 - 7 not known to be treated n/a n/a n/a Normal Care 
Glass, Natural & Man-Made
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
moldavite
(natural tektite glass)
6 not known to be treated n/a n/a n/a Normal, gentle care  
obsidian, rainbow obsidian, snowflake obsidian (natural volcanic glass) 6 not known to be treated n/a n/a n/a Avoid heat, chemicals, and ultrasonic cleaners.  
Lybian desert glass
(natural tektite glass)
6 not known to be treated n/a n/a n/a Normal, gentle care  
cat's eye glass, fiber optic glass 6 man made n/a n/a n/a Normal Care  
crystal (glass) 6 man-made n/a n/a n/a Normal Gentle Care  
glass, man-made 6 man-made n/a n/a n/a Normal Care  
goldstone (glass) 6 man-made n/a n/a n/a Normal Care  
helenite (glass) 5 - 6 man-made n/a n/a n/a Normal Care  
mandarin ice 5 - 6 man-made n/a n/a n/a Normal Care  
paraiba ice (glass) 5 - 6 man-made n/a n/a n/a Normal Care  
roman glass 5 - 6 man-made n/a n/a n/a Avoid household chemicals  
zandrite (glass) 5 - 6 man-made n/a n/a n/a Normal Care  
Goldenite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
goldenite, black (hornblende) 6 - 6.5 layered gold leaf adds gold veins always good Avoid abrasives, chemicals, and ultrasonic cleaners. CTD
goldenite, white 6 - 6.5 layered gold leaf adds gold veins always good Avoid abrasives, chemicals, and ultrasonic cleaners. CTD
Goldstone (glass)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
goldstone (glass) 5 - 6 man-made n/a n/a n/a Normal Care  
Goshenite, colorless beryl
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
goshenite, colorless beryl 7.5 - 8 not known to be treated n/a n/a n/a Normal Care 
Granite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
granite 5 - 7 not known to be treated n/a n/a n/a Normal Care  
5 - 7 waxed to improve appearance often fair to good Avoid heat, chemicals, ultrasonic cleaners W
azurite in granite 5 - 7 no treatment n/a n/a n/a Normal Care 
Larvikite - Gabbro (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling 
6 - 6.5 waxed to improve appearance occasionally fair to good Avoid harsh chemicals and ultrasonic cleanersW
Grossular Garnet
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
hessonite / imperial (grossular) 7 not known to be treated n/a n/a n/a Normal Care 
Mali (grossular-andradite) 6.5 - 7 not known to be treated n/a n/a n/a Normal Care 
Merelani mint garnet (grossular) 7 not known to be treated n/a n/a n/a Normal Care 
tsavorite (grossular) 7 not known to be treated n/a n/a n/a Normal Care 


Hayüne
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
haüyne / haüynit 5.5 - 6 not known to be treated n/a n/a n/a Normal, gentle handling
Helenite (glass)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
helenite (glass) 5 - 6 man-made n/a n/a n/a Normal Care
Heliodor (yellow beryl)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
heliodor (yellow beryl) 7.5 - 8 irradiated to produce color usually variable Normal Care, but some stones may fade in prolonged exposure to light or heat.IRR
Hematite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
hematite 5.5 - 6.5 not known to be treated n/a n/a n/a Normal Care
hematine 6.5 man-made n/a n/a n/a Normal Care
Hemimorphite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
hemimorphite 4.5 - 5 not known to be treated n/a n/a n/a Gentle care, moderately soft. Avoid ultrasonic cleaners.
Henanite (pietersite)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
henanite (pietersite) 6.5 not known to be treated n/a n/a n/a Normal Care 
Hessonite / Imperial (grossular)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
hessonite / imperial (grossular) 7 not known to be treated n/a n/a n/a Normal Care 
Hiddenite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
hiddenite 6.5 - 7 no treatment n/a n/a n/a Some stones cleave or fracture easily. Wear with care. 
6.5 - 7 irradiated to create color rarely poor Gentle care. Avoid prolonged exposure to light and heat to prevent color fading. Some stones cleave or fracture easily. Wear with care. Avoid ultrasonic cleanersIRR
Horn
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
horn 2.5 no treatment n/a n/a n/a Horn is a soft, organic product. Avoid heat, chemicals and ultrasonic cleaners. Requires gentle handling. 
2.5 heated to shape often fairHE
Howlite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
howlite white 6.5 no treatment n/a n/a n/a Normal Care 
howlite other colors 6.5 dyed/stained to add color commonly good to very good Avoid harsh chemicals, ultrasonic cleaners, and steaming.DYED
Hybrid
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
ruby (corundum) lead glass filling
Mahaleo Ruby
6 - 9 (will vary depending on the amount of glass filling used) filled color and clarity enhancement always will vary depending on the amount of glass filling used Special care required. Avoid ordinary household cleaners, acidic cleaners, acidic foods (lemon juice, vinegar, etc), steam and ultra sonic cleaners. Clean with a damp cloth.LGF
sapphire (corundum) lead glass filling 6 - 9 (will vary depending on the amount of glass filling used) filled color and clarity enhancement always will vary depending on the amount of glass filling used Special care required. Avoid ordinary household cleaners, acidic cleaners, acidic foods (lemon juice, vinegar, etc), steam and ultra sonic cleaners. Clean with a damp cloth.LGF
sapphire, pink (corundum) lead glass filling Mahaleo Sapphire 6 - 9 (will vary depending on the amount of glass filling used) filled color and clarity enhancement always will vary depending on the amount of glass filling used Special care required. Avoid ordinary household cleaners, acidic cleaners, acidic foods (lemon juice, vinegar, etc), steam and ultra sonic cleaners. Clean with a damp cloth.LGF
B-Jade 5 - 7 acid treated and filled to improve color and clarity always good stability Gentle care required: Avoid heat, harsh chemicals, and ultrasonic cleanersB-Jade
Hypersthene
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
hypersthene 5-6 not known to be treated n/a n/a n/a Moderately soft, so be mindful of scratching. Requires gentle handling.


Iolite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
iolite (cordierite) 7 - 7.5 not known to be treated n/a n/a n/a Normal Care
Ivory / Bone
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
ivory / bone 2 - 3 no treatment n/a n/a n/a Requires gentle handling. Bone and ivory are very soft and may discolor with time. Be mindful of scratching. 
2 - 3 bleached to improve color commonly good Bone and ivory are very soft and may discolor with time. Discoloration is due to porosity/absorption of body oils or other substances from wearing. Be mindful of scratching. Avoid chemicals and ultrasonic cleaners. Requires gentle handlingBL
2 - 3 dyed/stained to alter color or to look aged often goodDYED
2 - 3 impregnated to minimize porosity occasionally goodIMP


Jadeite & Nephrite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
jadeite jade
all colors
6.5 - 7 no treatment n/a n/a n/a Normal Care 
6.5 - 7 waxed/oiled to improve finish commonly good Avoid heat, harsh chemicals, and ultrasonic cleaners.W
6.5 - 7 Bleached/impregnated/dyed (B-Jade) to improve color and translucency frequently very good Gentle care required: Avoid heat, harsh chemicals, and ultrasonic cleaners.B-Jade
6.5 - 7 dyed/stained to add color frequently good Avoid strong light, chemicals, and ultrasonic cleaners.DYED
nephrite jade
all colors
6 - 6.5 no treatment n/a n/a n/a Normal Care 
6 - 6.5 dyed/stained to add color rarely unknown Avoid strong light, harsh chemicals, and ultrasonic cleaners. Discoloration may occur with time.DYED
Jasper (quartz)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
jasper (quartz) 6 - 6.5 no treatment n/a n/a n/a Normal Care  
6 - 6.5 dyed to add color sometimes good to very good Normal Care. Avoid heat, harsh chemicals, and ultrasonic cleaners. DYED
6 - 6.5 heated to enhance color sometimes excellent Normal Care HE
Jeremejevite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
jeremejevite 6.5 - 7.5 not known to be treated n/a n/a n/a Normal Care


Kornerupine
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
kornerupine 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid ultrasonic cleaners.
kornerupine cat's eye 6.5 not known to be treated n/a n/a n/a
Kunzite pink / violet
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
kunzite pink / violet 6.5 - 7 no treatment n/a n/a n/a Gentle care. Prolonged exposure to light, especially UV and sunlight, will cause fading. Can cleave or fracture easily. Wear with care. 
6.5 - 7 irradiated to improve color commonly fair to poorIRR
6.5 - 7 heated to improve color commonly fairHE
Kyanite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
kyanite, blue, orange, green, blue-green Bayadera Kyanite Nepalese Kyanite 5 & 7, depending on direction no treatment n/a n/a n/a Moderately soft and brittle, so be mindful of scratching. 
5 & 7, depending on direction heated to alter color rarely goodHE
5 & 7, depending on direction oiled/resin infused to improve clarity occasionally fair Moderately soft and brittle, so be mindful of scratching. Avoid heat, chemicals and ultrasonic cleaners. O


Labradorite (plagioclase feldspar)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
labradorite (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling 
6 - 6.5 oiled to improve appearance occasionally fair to good Avoid ultrasonic cleanersO
Labradorite Yellow (plagioclase feldspar)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
labradorite yellow (plagioclase feldspar) 6 - 6.5 no treatment n/a n/a n/a Normal, gentle handling 
6 - 6.5 irradiated to improve color commonly good Normal, gentle handling. Avoid heat.IRR
6 - 6.5 CVD coated to add color occasionally fair to good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.CVD
Lapis Lazuli
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
lapis lazuli 5 - 6 no treatment n/a n/a n/a Normal, gentle handling. Avoid exposure to acids, heat and ultrasonic cleaners. 
5 - 6 waxed/oiled to improve appearance commonly fairW
5 - 6 dyed to improve color commonly poor to goodDYED
5 - 6 lacquered to improve durability and appearance rarely goodCTD
Larimar
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
larimar (pectolite) 4.5 - 5 not known to be treated n/a n/a n/a Larimar is soft, so be mindful of scratching. Requires gentle handling 
4.5 - 5 stabilized/impregnated to improve stability and durability occasionally very good Gentle care, avoid heat and harsh chemicals. STB
Larvikite - Gabbro (plagioclase feldspar)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
larvikite - labbro (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. 
6 - 6.5 waxed to improve appearance occasionally fair to good Avoid harsh chemicals and ultrasonic cleanersW
Lazulite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
lazulite 5 - 6 not known to be treated n/a n/a n/a Avoid strong light, chemicals, and ultrasonic cleaners.
Lepidolite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
lepidolite 2.5 - 3 not known to be treated n/a n/a n/a Lepidolite is very soft, so be mindful of scratching. Requires gentle handling


Magnesite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
magnesite 4 dyed & stabilized to imitate other materials frequently very good Gentle care, avoid heat and harsh chemicals.DYED
Malachite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
malachite 3.5 - 4 no treatment n/a n/a n/a Malachite is very soft, so be mindful of scratching. Avoid chemicals, abrasives, heat and ultrasonic cleaners. 
3.5 - 4 coated with colorless wax to improve appearance occasionally fairW
3.5 - 4 impregnated with plastic or other hardening agents to improve appearance and durability often goodIMP
3.5 - 4 dyed to improve color uniformity occasionally goodDYED
Malaya Garnet, Malaia
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
malaya garnet, malaia 7 - 7.5 not known to be treated n/a n/a n/a Normal Care
Mandarin Ice
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
mandarin ice 5 - 6 man-made n/a n/a n/a Normal Care
Marble
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
marble 3 no treatment n/a n/a n/a Gentle care, moderately soft. Avoid ultrasonic cleaners, vinegar, harsh cleaners.  
3 dyed to add color frequently good to excellent Gentle care, moderately soft. Avoid ultrasonic cleaners, vinegar, harsh cleaners. DYED
3 lacquered to improve appearance and durability occasionally fair to good Gentle care, moderately soft. Avoid ultrasonic cleaners, vinegar, harsh cleaners. CTD
Marcasite (pyrite)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
marcasite (pyrite) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid acids and chemicals.
Maw Sit Sit
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
maw sit-sit 6 - 7 not known to be treated n/a n/a n/a Normal Care
Meteorite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
meteorite 3 - 4 no treatment n/a n/a n/a Normal Care  
3 - 4 lacquered to protect and prevent oxidization frequently good Normal, gentle handling. Avoid acids and chemicals. CTD
Moissanite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
moissanite 9 - 10 lab created n/a n/a n/a Normal Care  
9 - 10 lab created, CVD to create color occasionally very good Normal Care CVD
Moldavite (natural glass)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
moldavite
(natural glass)
5.5 not known to be treated n/a n/a n/a Normal, gentle care
Morganite pink, peach (beryl)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
morganite pink, peach (beryl) 7.5 - 8 no treatment n/a n/a n/a Normal Care 
7.5 - 8 heated to improve color frequently excellentHE
7.5 - 8 irradiated to produce color frequently excellentIRR
Moookaite Jasper
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
mookaite jasper 6 - 6.5 heated to enhance color usually excellent Normal CareHE
Moonstone, Adularia (orthoclase feldspar)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
moonstone, adularia (orthoclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care 
Mother of Pearl (shell)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
mother of pearl
(shell)
3 no treatment n/a n/a n/a Shell is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. In addition to above precautions: avoid perfumes, and hairsprays. 
3 dyed/stained to alter color commonly good to very goodDYED
3 stabilized to reduce porosity, to stabilize the stone sometimes fair to goodSTB
3 coated to protect shell and added design occasionally goodCTD
Muscovite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
muscovite 2.5 not known to be treated n/a n/a n/a Muscovite is very soft, so be mindful of scratching. Requires gentle handling


Natural Glass
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
moldavite
(natural glass)
5.5 not known to be treated n/a n/a n/a Normal, gentle care
obsidian
(volcanic glass)
5 - 5.5 not known to be treated n/a n/a n/a Avoid heat, chemicals, and ultrasonic cleaners.
glass, Lybian desert 5 - 5.5 not known to be treated n/a n/a n/a Normal, gentle care
Natural Rock
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
goldenite jade 6 - 6.5 layered gold leaf adds gold veins always good Avoid abrasives, chemicals, and ultrasonic cleaners.
rhyolite
(igneous rock)
6 - 7 not known to be treated n/a n/a n/a Normal Care
Nephrite Jade all colors
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
nephrite jade
all colors
6 - 6.5 no treatment n/a n/a n/a Normal Care 
6 - 6.5 dyed/stained to add color rarely unknown Avoid strong light, harsh chemicals, and ultrasonic cleaners. Discoloration may occur with time.DYED


Obsidian, Rainbow Obsidian, Snowflake Obsidian (natural volcanic glass)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
obsidian, rainbow obsidian, snowflake obsidian (natural volcanic glass) 6 not known to be treated n/a n/a n/a Avoid heat, chemicals, and ultrasonic cleaners.  
Opal
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
fire opal 5.5 - 6 no treatment n/a n/a n/a Avoid water, heat and solvents. Fire Opal is moderately soft, so be mindful of scratching. 
5.5 - 6 dyed/stained to add color sometimes goodDYED
dendritic opal 5.5 - 6 no treatment n/a n/a n/a Normal Care 
ethiopian opal 5 - 6 no treatment n/a n/a n/a Avoid steamers or ultrasonics; keep away from harsh cleaning agents or perfume; simply clean with a soft cloth. Keep away from any fluids or oils, as they can be absorbed and alter appearance and or crack the stone. Avoid all types of heat. 
5 - 6 dyed to add color commonly poor to excellentDYED
5 - 6 smoked to darken body color occasionally very good to excellentSM
blue opal (common opal) 6 - 6.5 no treatment n/a n/a n/a Normal Gentle Care 
boulder opal 6 no treatment n/a n/a n/a Normal Gentle Care 
6 oiled/resin infused to improve appearance occasionally fair Avoid heat, chemicals, ultrasonic, and repolishing.O
caramel spice opal (common opal) 6 no treatment n/a n/a n/a Avoid heat, chemicals, and ultrasonic cleaners. 
cat's-eye opal 6 impregnated to improve appearance and durability usually good Avoid heat, chemicals, and ultrasonic cleaners.IMP
common opal (non play-of-color opal) 6 - 6.5 no treatment n/a n/a n/a Normal gentle care 
common opal (non play-of-color opal) 6 - 6.5 dyed to add color occasionally fair to good Avoid steaming, chemicals, and ultrasonic cleanersDYED
mali green opal 6 - 6.5 no treatment n/a n/a n/a Normal gentle care 
matrix opal, leopard opal, yawa opal 6 or possibly lower no treatment n/a n/a n/a Normal gentle care 
5-6 stabilized/impregnated to improve stability and durability occasionally very good gentle care, avoid heat and harsh chemicalsSTB
6 or possibly lower Sugar Treated to darken color commonly very good Avoid heat, solvents, recutting and repolishing.SA
mosaic opal triplet, glass top 5 - 6 assembled product to create opal effect from smaller stones commonly fair to good Avoid heat, solvents, chemicals, ultrasonic, and repolishing.AS
mosaic opal triplet, quartz top 7 assembled product to create opal effect from smaller stones commonly fair to good Avoid heat, solvents, chemicals, ultrasonic, and repolishing.AS
opal doublet 6 assembled product to improve color and/or durability always fair to good Avoid heat, chemicals, ultrasonic, and repolishing.AS
opal triplet, glass top 5 - 6 assembled product to improve color and/or durability always fair to good Avoid heat, solvents, chemicals, ultrasonic, and repolishing.AS
opal triplet, quartz top 7 assembled product to improve color and/or durability always fair to good Avoid heat, solvents, chemicals, ultrasonic, and repolishing.AS
peruvian opal 6 not known to be treated n/a n/a n/a Avoid heat, chemicals, and ultrasonic cleaners. 
6 dyed to enhance color occasionally fair to good Avoid temperature changes, steaming, chemicals, and ultrasonic cleaners.DYED
prase opal (green opal) 6 - 6.5 no treatment n/a n/a n/a Normal, gentle care 
solid play-of-color opal, black, gray, white base 6 no treatment n/a n/a n/a Avoid excessive heat, solvents, and ultrasonic cleaners. 
6 impregnated, oiled/resin infused to help prevent crazing rarely fairIMP
6 coated on bottom to improve color occasionally fair to goodCTD
synthetic opal 6 lab created n/a n/a n/a Normal, gentle care 
Imitation opal (artificial polymer based) 4 - 5 man made n/a n/a n/a Normal care 
Orthoclase Feldspar
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
moonstone, adularia (orthoclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal Care 
orthoclase, various colors 6 - 6.5 not known to be treated n/a n/a n/a Normal Care 
sunstone (orthoclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid ultrasonic cleaners. 


Pallasitic Peridot
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
pallasitic peridot 6.5 no treatment n/a n/a n/a Normal gentle care 
Paraiba
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
paraiba / cuprian 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 oiled/resin infused to improve clarity sometimes fair to goodO
7 - 7.5 heated to improve color commonly excellentHE
paraiba ice (glass) 5 - 6 man-made n/a n/a n/a Normal Care  
Pearl
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
abalone pearl (natural pearl) 2.5 - 4 no treatment n/a n/a n/a Abalone is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. In addition to above precautions: avoid perfumes, and hairsprays. Requires gentle handling. 
conch pearl
(natural pearl)
3 - 4 no treatment n/a n/a n/a Avoid cosmetics, perfumes, hairsprays, heat and household chemicals. 
3 - 4 polishing/filling to repair n/a good 
cultured pearl freshwater & saltwater
(akoya, freshwater mussel, souffle)
3 - 4 no treatment n/a n/a n/a Avoid cosmetics, perfumes, hairsprays, heat and household chemicals. 
3 - 4 bleached to create more even color or lighten usually excellentBL
3 - 4 dyed/stained to add color commonly goodDYED
3 - 4 dyed/stained, potential colored nuclei to add color occasionally variableDYED
3 - 4 irradiated to create color occasionally very goodIRR
3 - 4 coated to even color, improve lustre often - increasingly common fair to goodCTD
cultured Tahitian, South Sea and keshi 3 - 4 no treatment n/a n/a n/a Avoid cosmetics, perfumes, hairsprays, heat and household chemicals. 
3 - 4 bleached to create more even color or lighten often very goodBL
3 - 4 dyed to add color commonly goodDYED
mabe 3 - 4 Assembled Product to improve color and durability always fair to very good Avoid cosmetics, perfumes, hairsprays, heat and household chemicals.AS
natural pearl 3 - 4 no treatment n/a n/a n/a Avoid cosmetics, perfumes, hairsprays, heat and household chemicals. 
3 - 4 polishing/filling to repair occasionally goodCTD
natural pearl
(scallop, conch, clam, oyster)
3 - 4 bleached to create more even color or lighten usually very good Avoid cosmetics, perfumes, hairsprays, heat and household chemicals.BL
3 - 4 dyed/stained w/-w/o heat to alter color rarely good to very goodDYED
Pearlfection™ 3 - 4 simulant n/a n/a n/a Normal gentle careDYED
souffle' pearls 3 - 4 standard pearl processing n/a n/a n/a Avoid cosmetics, perfumes, hairsprays, heat and household chemicals. 
Peridot
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
peridot 6.5 no treatment n/a n/a n/a Avoid sudden temperature changes, harsh chemicals, and ultrasonic cleaners. 
6.5 oiled/waxed to improve appearance rarely fair to good Avoid sudden temperature changes, harsh chemicals, and ultrasonic cleaners.O
Petalite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
petalite 6.5 no treatment n/a n/a n/a Normal Care 
6.5 irradiated to improve or alter color occasionally good IRR
Pezzotaite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
pezzotaite 8 not known to be treated n/a n/a n/a Normal Care
Phenakite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
phenakite 7.5 - 8 not known to be treated n/a n/a n/a Normal Care, but avoid sudden temperature changes.
Prasiolite (green quartz)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
prasiolite (green quartz) 7 irradiated/ annealed to alter color usually very good Avoid a jeweler's torch.IRR
Prehnite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
prehnite 6 - 6.5 not known to be treated n/a n/a n/a Normal Care, but avoid sudden temperature changes.
Psilomelane
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
psilomelane 6.5 no treatment n/a n/a n/a Normal Care
Phosphosiderite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
phosphosiderite 3.5 - 4 stabilized to improve stability and durability almost always very good Gentle care, moderately soft. Avoid ultrasonic cleaners, heat and harsh cleaners. STB
Pyrite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
marcasite (pyrite) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid acids and chemicals.  
pyrite 6 - 6.5 not known to be treated n/a n/a n/a  
3 - 4 gold plated to look like gold sometimes good CTD
rainbow(pyrite) 6 - 6.5 not known to be treated n/a n/a n/a  


Quartz
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
amethyst 7 no treatment n/a n/a n/a Normal Care 
7 heated/irradiated to improve color occasionally excellentHE/IRR
ametrine 7 no treatment n/a n/a n/a Normal Care 
7 heated to improve color occasionally excellentHE
blueberry quartz 7 irradiated /annealed to create color always excellent Normal careIRR
blue moon quartz 7 heated to create effect always excellent Normal CareHE
citrine
(all types)
7 no treatment n/a n/a n/a Normal Care 
7 heated to alter color usually excellentHE
lemon citrine, ouro verde quartz 7 irradiated to create color always excellent Normal CareIRR
dendritic quartz 7 no treatment n/a n/a n/a Normal Care 
7 heated to alter color rarely excellent Normal CareHE
7 irradiated to create color rarely good Avoid temperature changes, steaming, chemicals, and ultrasonic cleaners.IRR
drusy quartz 7 no treatment n/a n/a n/a Normal care 
7 coated to create color or iridescence often good Gentle care. Avoid abrasions. Chipping may reveal natural color. Cannot be re-cut or re-polished. Avoid heat, chemicals, and ultrasonic cleaners.CTD
7 CVD to create color or iridescence frequently very good Gentle care. Avoid abrasions. Chipping may reveal natural color. Cannot be re-cut or re-polished. Avoid heat, chemicals, and ultrasonic cleaners.CVD
7 heated to improve color occasionally excellent Normal careHE
latte quartz 7 irradiated/heated to alter color usually excellent Normal CareHE/IRR
lazulated quartz 7 not known to be treated n/a n/a n/a Avoid heat, temperature changes, steaming, chemicals, ultrasonic cleaners, and repolishing 
lilac quartz 7 heated to improve color occasionally excellent Normal CareHE
mookaite jasper 6 - 6.5 heated to enhance color usually excellent Normal CareHE
mystic quartz 7 CVD to create color effect always very good Gentle care. Avoid abrasions. Chipping may reveal natural color. Cannot be re-cut or re-polished. Avoid heat, chemicals, and ultrasonic cleaners.CVD
pietersite, henanite 7 not known to be treated n/a n/a n/a Normal Care 
prasiolite (green quartz) 7 irradiated/ annealed to alter color usually very good Avoid a jeweler's torch.IRR
quartz w/special inclusions
(actinolite, confetti, medusa, leopard, strawberry, iodolite)
7 not known to be treated n/a n/a n/a While they are a 7 in hardness, a proliferation of inclusions may alter this, either strengthening or weakening a material. 
quench crackled, emerald green 7 heated/cooled, dyed to add color and inclusions commonly very good Avoid heat, temperature changes, steaming, chemicals, ultrasonic cleaners, and re-polishing QCR
quench crackled 7 heated/cooled, dyed to add color and inclusions commonly good - poor, depending on type of dye usedQCR
rose quartz 7 no treatment n/a n/a n/a Normal Care 
7 dyed to add color commonly good Avoid heat, temperature changes, steaming, chemicals, ultrasonic cleaners, and repolishingDYED
rutilated quartz 7 not known to be treated n/a n/a n/a Normal Care 
smoky quartz 7 no treatment n/a n/a n/a Normal Care 
7 irradiated to create color usually goodIRR
rock crystal 7 not known to be treated n/a n/a n/a Normal Care 
hawk's-eye, blue tiger's eye 7 no treatment n/a n/a n/a Normal Care 
7 chemical bleaching with acid or bleaching agents to alter color occasionally excellentBL
tiger's-eye, brown 7 no treatment n/a n/a n/a Normal Care 
7 chemical bleaching with acid or bleaching agents to alter color occasionally excellentBL
tiger's-eye, red 7 heated to change from gold to red always excellent Normal CareHE
7 chemical bleaching with acid or bleaching agents to alter color sometimes excellentBL
7 dyed to alter color sometimes very good Avoid sudden temperature changes, chemicals, steam and ultrasonic cleaners.DYED
tourmalinated quartz 7 not known to be treated n/a n/a n/a Normal Care 
triplets, many patterns and colors 7 assembled with natural quartz top and bottom, colored or patterned layer in between to create new and interesting gems occasionally very good Avoid solvents, harsh chemicals and ultrasonic cleanersAS
Quartzite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
aventurine
(quartzite)
6.5 no treatment n/a n/a n/a Normal Care 
6.5 dyed to improve color often good to excellent Avoid abrasives, ultrasonic, solvents and heat.DYED
howlite white 6.5 no treatment n/a n/a n/a Normal Care 
howlite other colors 6.5 dyed/stained to add color commonly good to very good Avoid harsh chemicals, ultrasonic cleaners, and steaming.DYED
quartzite 6 - 6.5 no treatment n/a n/a n/a Normal Care 
6 - 6.5 dyed to alter color commonly excellent Avoid chemicals, heat and ultrasonic cleanersDYED
6 - 6.5 impregnated with colorless plastic to improve appearance, and durability commonly goodIMP


Rainbow calsilica
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
rainbow calsilica 3 - 4 composite n/a n/a n/a Gentle careCOMP
Rhodizite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
rhodizite 8 not known to be treated n/a n/a n/a Normal Care
Rhodochrosite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
rhodochrosite 3.5 - 4 not known to be treated n/a n/a n/a Rhodochrosite is very soft, so be mindful of scratching or chipping. Requires gentle handling.
Rhodolite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
rhodolite 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
Rhodonite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
rhodonite 5.5 - 6 no treatment n/a n/a n/a Normal, gentle handling 
5.5 - 6 dyed/stained to add color occasionally poor Normal, gentle handling. Avoid steam, chemicals and harsh cleaners.DYED
Rhyolite (natural rock)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
rhyolite (natural rock) 6 - 7 not known to be treated n/a n/a n/a Normal Care 
Rock Crystal
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
rock crystal 7 not known to be treated n/a n/a n/a Normal Care 
Rubellite (pink, red, purple tourmaline)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
Rubellite (pink, red, purple tourmaline) 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 heated to improve color occasionally excellentHE
7 - 7.5 irradiated to create color commonly excellentIRR
7 - 7.5 oiled/resin infused to improve appearance occasionally fair to good Avoid temperature changes, steaming, chemicals, and ultrasonic cleaners.O
7 - 7.5 dyed/stained to alter color rarely poor to fair Avoid abrupt temperature changes, steaming, chemicals, and ultrasonic cleaners.DYED
Ruby (corundum)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
ruby (corundum) 9 no treatment(extremely rare) n/a n/a n/a Normal Care 
9 heated to improve colorand clarity usually excellentHE
9 infilled - glass or flux filled to improve color and clarity commonly good to excellentINF
9 Beryllium lattice diffusion to improve color occasionally excellent Avoid recutting, otherwise Normal CareBE DIF
6 - 9 lead glass filled (fissure filled)
See Hybrid
to improve clarity and color commonly poor Avoid common household chemicals, steam cleaners, and ultrasonic cleaners .Avoid jewelers torches.LGF
6 - 9 flux healed to improve clarity commonly excellent Normal careFH
9 surface diffusion to create asterism or color occasionally good Avoid repolishing / recutting and scratching.DIF
9 dyed/stained with colored oils or polymers to improve color and clarity occasionally poor Avoid harsh chemicals, heat and ultrasonic cleaners.DYED
ruby beads 9 waxed/oiled to improve clarity and luster frequently poor Avoid harsh chemicals, heat and ultrasonic cleaners.W
star ruby all (corundum) 9 no treatment n/a n/a n/a Avoid jewelers torches, otherwise Normal Care 
6 - 9 lead glass filled (fissure filled) SeeHybrid to improve clarity and color occasionally poor to fair Avoid common household chemicals, steam cleaners, and ultrasonic cleaners. Avoid jeweler's torches.LGF
9 surface diffusion to implant star occasionally excellent Avoid repolishing / recutting, scratching and jeweler's torches.DIF
9 heated to improve color sometimes excellent Avoid jewelers torches, otherwise Normal CareHE
ruby - zoisite, anyolite 6.5 - 7 not known to be treated n/a n/a n/a Normal Care 
6.5 - 7 oiled to improve appearance occasionally fair Avoid ultrasonic and harsh cleaners.O
ruby, synthetic 9 lab created n/a n/a n/a Normal Care 
Rutile, synthetic
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
rutile, synthetic 6 - 6.5 lab created n/a n/a n/a Normal, gentle care 


Sandstone
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
sandstone 5 - 6 lab created n/a n/a n/a Normal, gentle care 
Sapphire
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
sapphire, blue (corundum) 9 no treatment(rare) n/a n/a n/a Normal Care 
9 heated to improve colorand clarity usually excellent Normal CareHE
9 dyed/stained with colored oils or polymers to improve color and clarity occasionally fair to good Avoid harsh chemicals, heat and ultrasonic cleaners.DYED
9 beryllium lattice diffusion to lighten color occasionally excellent Avoid recutting, otherwise Normal CareBE DIF
9 surface diffusion to create or improve color occasionally good Avoid chipping or repolishingDIF
6 - 9 lead glass filled (fissure filled) See Hybrid to add color and improve clarity sometimes fair to poor Avoid common household chemicals, steam cleaners, ultrasonic cleaners and a jewelers torch.LGF
sapphire, fancy (green, orange, purple, pink, padparadscha, yellow) (corundum) 9 no treatment n/a n/a n/a Normal Care 
9 heated to improve color and clarity usually excellent Normal CareHE
6 - 9 lead glass filled (fissure filled) See Hybrid to improve clarity and color occasionally poor Avoid common household chemicals, steam cleaners, ultrasonic cleaners, and jewelers torches.LGF
9 beryllium lattice diffusion to improve color commonly excellent Avoid recutting, otherwise Normal CareBE DIF
sapphire, star blue (corundum) 9 no treatment n/a n/a n/a Avoid jewelers torches, otherwise Normal Care 
9 heated improve color sometimes excellentHE
9 surface diffusion to implant star often excellent Avoid repolishing / recutting, scratching and jeweler's torches.DIF
6 - 9 lead glass filled (fissure filled) See Hybrid to improve clarity and color occasionally fair to poor Avoid common household chemicals, steam cleaners, and ultrasonic cleaners. Avoid jeweler's torches.LGF
sapphire, star gray - white (corundum) 9 no treatment n/a n/a n/a Avoid jewelers torches, otherwise Normal Care 
9 surface diffusion to implant star occasionally Excellent Avoid repolishing / recutting, scratching and jeweler's torches.DIF
sapphire, black star (corundum) 9 no treatment n/a n/a n/a Normal Care 
9 lacquered prevent flaking often fair Avoid harsh solvents and ultrasonic cleanersCTD
6 - 9 lead glass filled (fissure filled) See Hybrid reduce appearance of cracks commonly fair to poor Avoid common household chemicals, steam cleaners, and ultrasonic cleaners.LGF
sapphire, synthetic 9 lab created n/a n/a n/a Normal Care 
Sapphirine
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
sapphirine 7.5 not known to be treated n/a n/a n/a Normal Care
Scapolite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
scapolite yellow 5.5 - 6 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid jeweler's torch. 
scapolite violet 5.5 - 6 no treatment n/a n/a n/a Normal, gentle handling. Avoid jeweler's torch. 
5.5 - 6 irradiated to produce violet color rarely poor to fair Normal, gentle handling. Avoid jeweler's torch. When exposed to bright light color may fade.IRR
5.5 - 6 heated to produce violet color rarely goodHE
Scheelite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
scheelite 4.5 - 5 not known to be treated n/a n/a n/a Gentle care, not suitable for jewelry
Scolecite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
scolecite 5 - 5.5 not known to be treated n/a n/a n/a Soft and brittle, so be mindful of scratching. Not suitable for most jewelry uses. 
Septaria (mineral concretions)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
septaria (mineral concretions) varies not known to be treated n/a n/a n/a Normal, gentle care 
Serpentine
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
serpentine 2.5 - 6 no treatment n/a n/a n/a Serpentine is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. Requires gentle handling 
2.5 - 6 dyed/stained to alter color commonly fair to good Serpentine is very soft, so be mindful of scratching. Color may fade. Requires gentle handling. Avoid steam and heat, could remove dye.DYED
2.5 - 6 impregnated, waxed/oiled to improve hardness and luster commonly good to very good Serpentine is very soft, so be mindful of scratching. Avoid ultrasonic, chemicals, and solvents. Requires gentle handlingIMP
Shanseres (diopside)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
shanseres (diopside) 5.5 not known to be treated n/a n/a n/a Diopside is moderately soft, so be mindful of scratching. Avoid abrasives and solvents.  
Shark teeth
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
shark teeth 3 - 4 not known to be treated n/a n/a n/a Most shark teeth are actually fossils. Gentle Care. 
Shell
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
abalone
(shell)
3 no treatment n/a n/a n/a Shell is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. In addition to above precautions: avoid perfumes, and hairsprays. 
3 dyed to add color commonly goodDYED
3 stabilized prevent porosity occasionally fairSTB
mother of pearl
(shell)
3 no treatment n/a n/a n/a Shell is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. In addition to above precautions: avoid perfumes, and hairsprays.  
3 dyed/stained to alter color commonly good to very goodDYED
3 stabilized to reduce porosity, to stabilize the stone sometimes fair to goodSTB
3 coated to protect shell and added design occasionally goodCTD
shell
(oyster, paua, conch, clam, scallop)
3 no treatment n/a n/a n/a Shell is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. In addition to above precautions: avoid perfumes, and hairsprays.  
3 dyed/stained to alter color commonly fair to goodDYED
3 stabilized to reduce porosity, to stabilize the stone commonly fair to goodSTB
3 coated to protect shell and added design occasionally goodCTD
Sillimanite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
sillimanite 6 - 7 not known to be treated n/a n/a n/a Normal, gentle handling.
sillimanite cat's eye 6 - 7 not known to be treated n/a n/a n/a
Sinhalite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
sinhalite 6.5 not known to be treated n/a n/a n/a Gentle care, moderately soft. Avoid ultrasonic cleaners.
Sodalite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
sodalite 5.5 - 6 no treatment n/a n/a n/a Normal Care 
5.5 - 6 dyed/stained to improve color sometimes fair Avoid cleaners, chemicals, steam and ultra sonic cleaners.DYED
Spessartite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
spessartite 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
Sphene
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
sphene 5 - 5.5 no treatment n/a n/a n/a Sphene is a soft stone, so be mindful of scratching. 
5 - 5.5 heated to create red or orange color occasionally goodHE
Sphalerite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
sphalerite 3.5 - 4 not known to be treated n/a n/a n/a Sphalerite is a very soft stone, so be mindful of scratching. It is generally not suited for jewelry use.
Spinel
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
spinel 8 not known to be treated n/a n/a n/a Normal Care  
8 heated to improve color and clarity rarely excellent Normal Care HE
black spinel 8 not known to be treated n/a n/a n/a Normal Care  
Spodumene
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
hiddenite 6.5 - 7 no treatment n/a n/a n/a Some stones cleave or fracture easily. Wear with care. 
6.5 - 7 irradiated to create color rarely poor Gentle care. Avoid prolonged exposure to light and heat to prevent color fading. Some stones cleave or fracture easily. Wear with care. Avoid ultrasonic cleanersIRR
kunzite pink / violet 6.5 - 7 no treatment n/a n/a n/a Gentle care. Prolonged exposure to light, especially UV and sunlight, will cause fading. Some stones cleave or fracture easily. Wear with care. 
6.5 - 7 irradiated to improve color commonly fair to poorIRR
6.5 - 7 heated to improve color commonly fairHE
Teradora™, yellow spodumene, Canary spodumene 6.5 - 7 no treatment n/a n/a n/a Gentle care. Prolonged exposure to light, especially UV and sunlight, will cause fading. Some stones cleave or fracture easily. Wear with care. 
6.5 - 7 irradiated to create color frequently poor Gentle care. Prolonged exposure to light, especially UV and sunlight, will cause fading. Some stones cleave or fracture easily. Wear with care.IRR
Strontium titanate
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
strontium titanate 5 - 5.5 lab created n/a n/a n/a Normal, gentle handling Strontium Titanate is a soft stone, so be mindful of scratching. 
Sugilite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
sugilite 6 no treatment n/a n/a n/a Normal Care 
6 dyed to improve color occasionally good Avoid solvents, steam and ultrasonic cleaners.DYED
Sunstone
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
sunstone (orthoclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid ultrasonic cleaners. 
sunstone (plagioclase feldspar) 6 - 6.5 not known to be treated n/a n/a n/a Normal, gentle handling. Avoid ultrasonic cleaners. 
6 - 6.5 oiled to improve appearance occasionally fair to good Avoid ultrasonic cleaners. O


Taaffeite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
taaffeite 8 not known to be treated n/a n/a n/a Normal Care and handling
Tanzanite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
tanzanite 6.5 no treatment (rare) n/a n/a n/a Normal, gentle handling 
6.5 heated to improve color almost always excellentHE
6.5 coated to improve color rarely fair Gentle wear, avoid ultrasonics and high heat.CTD
green tanzanite, ocean tanzanite 6.5 no treatment n/a n/a n/a Normal, gentle handling 
6.5 heated to improve color frequently excellent HE
yellow, pink, orange, colorless (tanzanite) 6.5 no treatment n/a n/a n/a Normal, gentle handling 
6.5 heated to improve color sometimes excellent HE
Tektite Glass
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
moldavite
(natural tektite glass)
6 not known to be treated n/a n/a n/a Normal, gentle care  
Lybian desert glass
(natural tektite glass)
6 not known to be treated n/a n/a n/a  
tektite (natural glass) 6 not known to be treated n/a n/a n/a  
Tiger's eye
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
hawk's-eye, blue tiger's eye 7 no treatment n/a n/a n/a Normal Care  
7 chemical bleaching with acid or bleaching agents to lighten color occasionally excellent BL
tiger's-eye, brown 7 no treatment n/a n/a n/a Normal Care  
7 chemical bleaching with acid or bleaching agents to lighten color occasionally excellent BL
tiger's-eye, red 7 heated to change from gold to red usually excellent Normal Care HE
7 chemical bleaching with acid or bleaching agents to lighten color occasionally excellent BL
7 dyed to alter color occasionally very good Avoid sudden temperature changes, chemicals, steam and ultrasonic cleaners. DYED
pietersite, henanite 7 not known to be treated n/a n/a n/a Normal Care  
Topaz
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
blue topaz - sky, swiss, london, super 8 irradiated and annealed to create color almost always excellent Normal CareIRR
8 CVD coated to add color occasionally fair to good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.CVD
brown, champage 8 no treatment n/a n/a n/a May fade with exposure to sunlight. 
8 irradiated to create color occasionally variesIRR
green 8 irradiated to create color occasionally fair to poor Color fades in exposure to sunlight and high heat.IRR
8 CVD coated to add color commonly fair to good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.CVD
mystic series,pink, red, ocean, glacier, patriot, canary, champagne, orchid, dawn, teal, kiwi, etc. 8 CVD coated to add color commonly fair to good Avoid repolishing, scratching or abrading - color coating may be chipped or scratched off.CVD
imperial 8 no treatment n/a n/a n/a Normal Care 
8 heated to improve color usually excellent Normal CareHE
8 irradiated to improve color sometimes variable Avoid heat and strong light.IRR
yellow / orange 8 irradiated to create color occasionally variable Avoid heat and strong light.IRR
8 heated to improve color usually excellent Normal CareHE
white (colorless) 8 no treatment n/a n/a n/a Normal Care 
8 heated to remove color occasionally excellentHE
Tourmaline
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
indicolite 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 heated to improve color commonly excellentHE
7 - 7.5 oiled/resin infused to improve appearance occasionally fair to good Avoid steaming, harsh chemicals, ultrasonic, and temperature changes.O
achroite, colorless 7-7.5 not known to be treated n/a n/a n/a Normal Care 
bi-color, parti-color 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 heated to improve color commonly excellentHE
cat's-eye tourmaline 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 oiled/resin infused to improve clarity occasionally good Avoid steaming, harsh chemicals, ultrasonic, and temperature changes. O
chrome tourmaline 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
dravite (brown tourmaline) 7 - 7.5 not known to be treated n/a n/a n/a Normal Care 
green, blue 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 heated to improve color commonly excellentHE
7 - 7.5 oiled/resin infused to improve appearance occasionally fair to good Avoid steaming, chemicals, ultrasonic cleaners, and temperature changes. O
paraiba / cuprian 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 oiled/resin infused to improve clarity sometimes fair to goodO
7 - 7.5 heated to improve color commonly excellentHE
pink, red (rubellite), purple 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 heated to improve color occasionally excellentHE
7 - 7.5 irradiated to create color commonly excellentIRR
7 - 7.5 oiled/resin infused to improve appearance occasionally fair to good Avoid temperature changes, steaming, chemicals, and ultrasonic cleaners. O
7 - 7.5 dyed/stained to alter color rarely poor to fair Avoid steaming, chemicals, ultrasonic cleaners, and temperature changes.DYED
schorl (black tourmaline) 3 no treatment n/a n/a n/a Gentle handling (specimen)  
yellow / orange 7 - 7.5 no treatment n/a n/a n/a Normal Care  
7 - 7.5 heated to improve color occasionally excellentHE
7 - 7.5 irradiated to create color rarely very goodIRR
watermelon 7 - 7.5 no treatment n/a n/a n/a Normal Care 
7 - 7.5 heated to improve color commonly excellentHE
Trapiche Emerald
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
trapiche emerald 7.5 - 8 oiled/resin infused to improve clarity almost always fair to good, may require maintenance Avoid extreme heat, steaming, chemicals and ultrasonic cleaners.O
7.5 - 8 dyed/stained to alter color occasionally variable Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.DYED
Tremolite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
tremolite 5 - 6 not known to be treated n/a n/a n/a Gentle care, tremolite can be brittle as well as cleave.
Trilobites
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
trilobites 3 - 4 not known to be treated n/a n/a n/a Normal, gentle care care  
Tsavorite Garnet
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling on-air code
tsavorite garnet (grossular) 7 not known to be treated n/a n/a n/a Normal Care 
Turquoise
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
turquoise 5 - 6 no treatment n/a n/a n/a Gentle care, natural turquoise is very soft and porous, so avoid contact with oils and colored fluids. Clean with clean damp cloth only. 
5 - 6 impregnated, waxed to improve color and luster commonly poor to fair Avoid hot water, household chemicals, steam and ultrasonic cleaners.IMP
5 - 6 dyed & stabilized to improve color and durability often very goodDYED
4 - 6 composite to make larger pieces from powder or smaller pieces commonly very goodCOMP
5 - 6 stabilized to improve durability and appearance commonly very goodSTB
5 - 6 Zachary Process to improve durability and appearance proprietary process very goodZPR
Kingman turquoise – blue, green, purple 5 - 6 composite to make larger stones from smaller pieces, add color, stabilize, and add metallic veining commonly very good Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.COMP
purple turquoise 5 - 6 composite to make larger stones from smaller pieces, add color, stabilize, and add metallic veining commonly very good Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.COMP


Ulexite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
ulexite 2.5 no treatment n/a n/a n/a Avoid hot water, household chemicals, and ultrasonic cleaners 
2.5 coated to improve durability sometimes goodCTD
Unakite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
unakite 6 - 6.5 No Treatment n/a n/a n/a Normal Care 
6 - 6.5 Impregnated to improve durability rarely good Avoid hot water, household chemicals, and ultrasonic cleanersIMP
Uvarovite Garnet
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
uvarovite garnet 6.5 - 7 not known to be treated n/a n/a n/a Normal Care 


Variscite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
variscite 4 - 4.5 no treatment n/a n/a n/a Normal, gentle handling. Variscite is a soft stone, so be mindful of scratching. 
4 - 4.5 stabilized to improve durability and for shaping and polishing commonly good Avoid exposure to hot water, heat, steam, chemicals and ultrasonic cleanersSTB
4 - 4.5 stabilized & dyed to improve color and durability commonly very good Avoid temperature changes, heat, steaming, chemicals, and ultrasonic cleaners.DYED
4 - 4.5 dyed/stained to improve color often fair to good Avoid temperature changes, heat, steaming, chemicals, and ultrasonic cleaners.DYED
Vesuvianite (idocrase)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
vesuvianite (idocrase) 6.5 not known to be treated n/a n/a n/a Moderately soft, so be mindful of scratching 
Viridine (andalusite)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
viridine 7 - 7.5 no treatment n/a n/a n/a Normal Care 


Witherite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
witherite 3.5 not known to be treated n/a n/a n/a Very soft and may be attacked by acids. Not suitable for jewelry.
Wulfenite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handling
wulfenite 2.5 - 3 not known to be treated n/a n/a n/a Very soft , careful handling


YAG (yttrium aluminum garnet)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
YAG (yttrium aluminum garnet) 8.5 lab created n/a n/a n/a Normal care 


Zandrite (glass)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
zandrite (glass) 5 - 6 man-made n/a n/a n/a Normal Care  
Zircon
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
blue 7.5 heated to create blue almost always fair to good Avoid sharp knocks and harsh wear. Avoid prolonged exposure to UV lighting, such as tanning beds and nail polish curing lights, to avoid temporary alteration of color.HE
colorless 7.5 heated to lighten color almost always fair to goodHE
green / brown 6.5 - 7.5 not known to be treated n/a n/a n/a Avoid sharp knocks and harsh wear.  
hyacinth, pink 7.5 no treatment n/a n/a n/a 
7.5 heated to produce color frequently goodHE
imperial 7.5 heated to produce color almost always goodHE
red 7.5 no treatment n/a n/a n/a 
7.5 heated to improve color commonly goodHE
yellow 7.5 no treatment n/a n/a n/a 
7.5 heated to improve color occasionally goodHE
fancy color zircon 7.5 CVD to add color occasionally good to very good Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.CVD
Zoisite
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
ruby - zoisite, anyolite 6.5 - 7 not known to be treated n/a n/a n/a Normal Care 
6.5 - 7 oiled to improve appearance occasionally fair Avoid ultrasonic and harsh cleaners.O
tanzanite 6.5 no treatment (rare) n/a n/a n/a Normal, gentle handling 
6.5 heated to improve color almost always excellentHE
6.5 coated to improve color rarely fair Gentle wear, avoid ultrasonics and high heat.CTD
green tanzanite, ocean tanzanite 6.5 no treatment n/a n/a n/a Normal, gentle handling 
6.5 heated to improve color frequently excellent HE
yellow, pink, orange, colorless (tanzanite) 6.5 not known to be treated n/a n/a n/a Normal, gentle handling 
6.5 heated to improve color sometimes excellent HE
Zultanite™ (diaspore)
gemstone/types hardness enhancement method(s) purpose frequency stability/durability care and handlingon-air code
zultanite™ (diaspore) 6.5 - 7 not known to be treated n/a n/a n/a Cleaves easily, or is known to brittleness. Avoid ultrasonic cleaners. Wear with care. 
cat's eye zultanite™ (diaspore) 6.5 - 7 oiled to improve appearance commonly fair Cleaves easily, or is prone to brittleness. Avoid ultrasonic cleaners, heat and chemicals. Wear with care.O
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