Grossularite

saf-ahyuh r
January Birthstone

The first grossular garnet specimens discovered were pale green and similar in color to the gooseberry. This species of garnet gets its name from the Latin name for gooseberry "Grossularia". Not all grossular garnets are green. Most grossular garnets are better known by their variety names hessonite, tsavorite, mint, leuco garnet, and hydrogrossular.

Grossularite Polished
Grossularite Classification
Common Name Grossularite
Species Garnet
Grossularite Optical Properties
Transparency Translucent-Transparent
Dispersion Strength: Moderate Fire Value: 0.027
Refractive Index 1.730-1.760
Optic Character NA
Optic Sign NA
Polariscope Reaction Anomalous Double Refraction (ADR), Singly Refractive (SR)
Fluorescence SWUV: Colorless or mint: weak yellow-orange; Yellow: Inert to weak orange
LWUV: Colorless or mint: inert to weak orange; Yellow: Inert to weak orange, pink or red
CCF Reaction None
Grossularite Characteristic Physical Properties
Hardness 7-7.5
Streak None
Specific Gravity 3.570-3.730
Toughness Good
Inclusions Hessonite garnet rounded crystals and "scotch and water" effect; Tsavorite or mint garnet fingerprints, healed fractures, graphite.
Luster Vitreous
Stability Good
Fracture Irregular, uneven, conchoidal
Cleavage None
Grossularite Chemistry & Crystallography
Chemical Name calcium aluminum silicate
Chemical Formula Ca3Al2(SiO4)3
Crystal System Cubic
Chemistry Classification Silicate

Grossularite Colors

  • Brown Grossularite Brown
  • Yellow Grossularite Yellow
  • Green Grossularite Green
  • Red Grossularite Red
  • White Grossularite White
  • Gray Grossularite Gray
  • Black Grossularite Black

Grossularite Spectra

Grossularite Spectra
GROSSULAR GARNET

Color mainly due to manganese. Absorption in the areas around 505nm. and 527nm. General absorption of the yellow

Jewelry Television acknowledges the significant scientific contributions of John S Harris, FGA to the study of gemstone spectra and with deep appreciation to him, acknowledges the use of his images and related notes about gemstones and their spectra in the educational materials on this website.

Alternate Names

Hessonite, cinnamon stone, tsavorite, mint garnet, leuco garnet, hydrogrossular, grossular

Countries of Origin

Myanmar; Papua New Guinea; Angola; Cambodia; Malaysia; Kazakhstan; Portugal; Oman; Greece; Austria; Mongolia; Korea (the Republic of); Morocco; Mali; Brazil; Algeria; Iraq; Tonga; Colombia; Ecuador; Argentina; United States of America (the); Hungary; Japan; Ukraine; Taiwan (Province of China); Bolivia (Plurinational State of); India; New Zealand; Canada; Turkey; Namibia; Finland; Honduras; Italy; South Africa; Antarctica; Jamaica; Peru; Germany; Tanzania, United Republic Of; Afghanistan; Czechia; Guinea; Egypt; Madagascar; Sierra Leone; Saudi Arabia; Sweden; Pakistan; China; Ireland; Russian Federation (the); Poland; Slovakia; Bulgaria; France; Jordan; Kyrgyzstan; United Kingdom of Great Britain and Northern Ireland (the); Romania; Sri Lanka; Dominican Republic (the); Kenya; Switzerland; Spain; Cuba; Nicaragua; Norway; Botswana; Mexico; Zimbabwe; Australia; Greenland; Indonesia

Care

Normal care

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Species/Variety

Hessonite

Nicknamed the "cinnamon stone", hessonite is a variety of grossular garnet and comes in two colors, golden and cinnamon. A perfectly colored hessonite is a bright golden orange that resembles a combination of honey and orange with an internal fire. Some hessonites have tints of red and brown with cinnamon appearance. Hessonite is common in the gem gravels of Sri Lanka and practically all hessonite is obtained from this locality, although it is also found in Africa. While the clearest gems are most prized, inclusions in hessonite are common, with unique toffee-like streaks giving hessonite an oily or even glass-like appearance.

Hessonite Grossularite
Hessonite Classification
Common Name Hessonite
Hessonite Optical Properties
Refractive Index 1.74 typical
CCF Reaction None
Hessonite Characteristic Physical properties
Specific Gravity 3.57
Toughness Good
Inclusions Stubby, rounded included crystals. Shows oily, "heat wave" or "scotch in water" effect.
Stability Good

Mali Garnet

Mali garnet is one of the latest discoveries in the garnet family. This attractive and very interesting rare mixture of andradite and grossular was only discovered in late 1994 at the Sandar Mine in Mali's Kayes region (Diakon Arrondissement). Extremely rare, Mali garnets are a bright, uniform light yellowish green color.

Mali Garnet Grossularite
Mali Garnet Classification
Common Name Mali Garnet
Mali Garnet Optical Properties
Refractive Index 1.752-1.779
Fluorescence SWUV: Inert
LWUV: Inert
Mali Garnet Characteristic Physical properties
Specific Gravity 3.64
Toughness Good
Inclusions Many Mali garnet stones are inclusion free but sometimes small mineral crystals and fingerprints are found along with parallel growth planes.
Stability Good

Leuco Garnet

Leuco garnet is the colorless variety of grossular garnet. The colorless variety is extremely rare. Known specimens have come from Myanmar and Sri Lanka.

Leuco Garnet Grossularite
Leuco Garnet Classification
Common Name Leuco Garnet
Leuco Garnet Optical Properties
Refractive Index 1.74 typical
CCF Reaction None
Leuco Garnet Characteristic Physical properties
Specific Gravity 3.57
Toughness Good
Inclusions Might contain mineral inclusions or healed fractures
Stability Good

Mint Garnet

Mint garnet is the pale green variety of grossular garnet that gets its color from trace amounts of vanadium and chromium. Gemstones are typically under 1 ct. It is indicator gem for tanzanite and has been found in Tanzania, Kenya, and Madagascar. It has the nickname “UV garnet” because most stones florescence a peachy orange in Long Wave Ultraviolet light.

Mint Garnet Grossularite
Mint Garnet Classification
Common Name Mint Garnet
Mint Garnet Optical Properties
Refractive Index 1.74 typical
CCF Reaction None
Mint Garnet Characteristic Physical properties
Specific Gravity 3.57
Toughness Good
Inclusions Rounded mineral inclusions, silk
Stability Good

Rosolite, Landerite or Xalostocite

Rosolite which is sometimes called landerite or xalostocite is found in Sierra de Cruces, Mexico. It is the translucent to opaque variety of grossular garnet found in marble.

Rosolite, Landerite or Xalostocite Grossularite
Rosolite, Landerite or Xalostocite Classification
Common Name Rosolite, Landerite or Xalostocite
Rosolite, Landerite or Xalostocite Characteristic Physical properties
Specific Gravity 3.57
Toughness Good
Inclusions Included
Stability Good

Tsavorite

Tsavorite is one of two green varieties of garnet, though arguably the more important of the two. Especially in smaller sizes, tsavorite creates competition for emerald because it is less included, rarely treated and more durable. Like some emerald and green tourmaline, tsavorite garnet owes its green hues to the presence of vanadium and chromium. First discovered in Tanzania in 1967 and a few years later in Kenya, tsavorite's name pays homage to the nearby Tsavo National Park.

Tsavorite Grossularite
Tsavorite Classification
Common Name Tsavorite
Tsavorite Optical Properties
Refractive Index 1.74 typical
CCF Reaction Some stones may appear pink or red
Tsavorite Characteristic Physical properties
Specific Gravity 3.57
Toughness Good
Inclusions Tsavorite garnet is a Type II clarity stone. Stones will sometimes have feathers, fingerprint inclusions, needles, asbestos fibers and small graphite platelets
Stability Good

Hydrogrossular Garnet

Hydrogrossular garnet is typically translucent to opaque and is usually available as cabochons, but on rare occasion may be found as transparent, faceted gemstones. Generally seen as green to blue-green, pink, white, and gray, this gemstone may contain small dark gray to black inclusions and may look similar to jade if opaque. Hydrogrossular is a variety of grossular garnet where hydroxide partially replaces silica.

Hydrogrossular Garnet Grossularite
Hydrogrossular Garnet Classification
Common Name Hydrogrossular Garnet
Hydrogrossular Garnet Optical Properties
Refractive Index 1.72 typical
CCF Reaction Green: possibly pinkish
Hydrogrossular Garnet Characteristic Physical properties
Specific Gravity 3.13
Toughness Good
Inclusions Might have black magnetite inclusions that resemble pepper.
Stability Good
Tim Matthews

Author

Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.