Chrysoberyl

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Chrysoberyl is the name of a mineral as well as three different gem varieties--two of which are widely accepted as some of the most rare and valuable of all phenomenal gems. The gem commonly known as chrysoberyl is a yellowish-green, brownish-yellow, or colorless transparent to translucent mineral that is usually faceted into gems and generally considered a collector's stone. While not often set in jewelry, its characteristics make it ideal for such use. When chrysoberyl displays color-change properties, it is known as alexandrite, and when it exhibits chatoyancy, it is known as cat's eye chrysoberyl.

Chrysoberyl Polished
Chrysoberyl Classification
Common Name Chrysoberyl
Species Chrysoberyl
Chrysoberyl Optical Properties
Transparency Transparent - Opaque
Dispersion Strength: Weak Fire Value: 0.015
Refractive Index 1.746-1.755
Tolerance:(+0.004/-0.006)
Birefringence 0.008- 0.010
Optic Character Biaxial
Optic Sign Positive
Polariscope Reaction Doubly Refractive (DR)
Fluorescence SWUV: Inert to yellowish green in yellow and greenish stones
LWUV: Could be red for "mint" chrysoberyl
Pleochroism Trichroic, weak
Chrysoberyl Characteristic Physical Properties
Hardness 8.5
Streak White
Specific Gravity 3.710-3.750 Range:+/-0.02 Typical:3.730
Toughness Varies
Inclusions Transparent green and yellow chrysoberyl are type I clarity stones. Stones might show twinning planes, feathers, fingerprints, silk, elongated tubes and needles.
Luster Bright Vitreous
Stability Very Good
Fracture Conchoidal
Cleavage Good, in one direction
Chrysoberyl Chemistry & Crystallography
Chemical Name beryllium aluminum oxide
Chemical Formula BeAl2O4
Crystal System Orthorhombic
Chemistry Classification Oxide

Chrysoberyl Colors

  • Brown Chrysoberyl Brown
  • Yellow Chrysoberyl Yellow
  • Green Chrysoberyl Green

Chrysoberyl Spectra

Chrysoberyl Spectra
CHRYSOBERYL

Color due to iron. The strong absorption here centered at 444nm. In the deep blue covers an area of about 15nm. indicating a high iron content

Chrysoberyl Spectra
CHRYSOBERYL

Color due to iron. The diagnostic feature here is the strong iron band centered at 444nm. It may be accompanied by a weaker, narrower band at 485nm. This band at 444nm. is a useful guide in distinguishing Chrysoberyl "Cats Eye" from the Quartz "Cats Eye

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

Cymophane

Countries of Origin

Tanzania, United Republic Of; Myanmar; Afghanistan; Unknown; Sri Lanka; Russian Federation (the); Brazil; Madagascar; India

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Creation Classification

Lab Created

Synthetic chrysoberyl is produced by a process called the Czochralski method.Material containing the elements that make up the mineral chrysoberyl (beryllium, aluminum and oxygen) are melted in a platinum crucible along with elements that produce the desired color (in this case, iron).A small chrysoberyl crystal (called a seed) attached to a rod is then dipped into the melt and slowly pulled away as the crystal grows around the seed.For this reason, the Czochralski method is also known as crystal pulling.Synthetic gems have the same chemical, optical, and physical properties of their natural counterparts, but are a more cost-effective alternative to a natural gem.

Lab Created Chrysoberyl
Lab Created Classification
Common Name Lab Created
Lab Created Optical Properties
Fluorescence LWUV: Inert to Weak Red
Pleochroism Trichroic, weak to moderate, varying shades of body color
Lab Created Characteristic Physical properties
Specific Gravity 3.71
Inclusions Synthetic chrysoberyl might show curved striae growth structure, gas bubbles and have needle like inclusions.

Optical Phenomena

Cat's Eye

The term cat's eye is used to describe a phenomenal optical property in gemstones, but in this case, chrysoberyl. Known as chatoyancy, this effect appears as a bright, narrow slit--similar to the pupils in the eyes of your favorite feline. This phenomenon is caused by the presence of parallel fibrous or needle-like inclusions that interfere with the passage of light through the crystal, scattering and reflecting light back to the viewer as a thin line.

Cat's Eye Chrysoberyl
Cat's Eye Classification
Common Name Cat's Eye
Cat's Eye Optical Properties
Pleochroism Unobservable
Cat's Eye Characteristic Physical properties
Inclusions Cat's-eye chrysoberyl will have parallel rutile needles or hollow growth tubes parallel to the c-axis that have give the appearance of silk. Stone can contain fingerprints or liquid inclusions and have angular included crystals.Stone might show twinning
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.