Chrysoberyl Gemstone & Information | Gemopedia by JTV | Gemopedia™
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.
Yellow To Yellowish Green, Greenish Brown, Bluish Green
Chrysoberyl classificationCommonNameChrysoberylSpeciesChrysoberylVarietyColorsYellow To Yellowish Green, Greenish Brown, Bluish GreenAlternateNamesGemstoneGroupsKeySeparationsrefractive index, birefringence, pleochroism and spectrum. Spectrum should reflect a strong diagnostic band at 444nm.ClassificationCommentsPhenomenal chrysoberyl may exhibit chatoyancy, in which case it is classified as "cat's-eye chrysoberyl." Misnomer: oriental chrysolite.
Chrysoberyl chemistry & crystallographyChemicalNameberyllium aluminum oxideChemicalFormulaBeAl2O4SynthesisCrystalSystemOrthorhombicChemistryClassificationOxideNatureNaturalCrystallinityCrystallineChemistryComments
Chrysoberyl optical propertiesTransparencyTransparent - OpaqueDispersionStrength: weak fire Value: 0.015OpticalCommentsRefractiveIndex1.746-1.755
Tolerance:(+0.004/-0.006)Birefringence0.008-0.01OpticCharacterBiaxialOpticSignPositivePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: Inert to yellowish green in yellow and greenish stones
LWUV: Could be red for "mint" chrysoberylCCFReactionPleochroismTrichroic, weak
Chrysoberyl characteristic physical propertiesHardness8.5CharacteristicCommentsStreakWhiteSpecificGravity3.71-3.75 Range:+/-0.02 Typical:3.73ToughnessVariesInclusionsTransparent green and yellow chrysoberyl are type I clarity stones. Stones might show twinning planes, feathers, fingerprints, silk, elongated tubes and needles.LusterBright VitreousStabilityVery GoodFractureConchoidalCleavageGood, in one direction