Alexandrite (Synthetic) Gemstone & Information | Gemopedia by JTV | Gemopedia™
Some gems, like alexandrite, are almost impossible to find in nature today, much less in the sizes and quality people dream of owning. Synthetic alexandrite can be created in a variety of ways including flux growth, Czochralski method, or floating zone method. 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.
Bluish Green In Daylight, Fluorescent Light, Brownish Red To Purple-Red In Incandescent
Alexandrite-synthetic classificationCommonNameAlexandrite (Synthetic)SpeciesChrysoberylVarietySynthetic AlexandriteColorsBluish Green In Daylight, Fluorescent Light, Brownish Red To Purple-Red In IncandescentAlternateNamesGemstoneGroupsKeySeparationsColor change, refractive index, birefringence, pleochroism and spectrum help identify alexandrite, but magnification is important to distinguish synthetic from natural. Natural material might show stepped twin planes, feathers and elongated tubes or needles. Strong red fluorescence is a key indicator of synthetic.ClassificationCommentsAlexandrite's spectrum varies by direction, showing a different spectrum in the green direction than in the purple-red pleochroic direction. Cat's-eye synthetic alexandrite is also produced.
Alexandrite-synthetic chemistry & crystallographyChemicalNameberyllium aluminum oxideChemicalFormulaBeAl2O4Synthesisflux growth, pulled or floating zoneCrystalSystemOrthorhombicChemistryClassificationOxideNatureSyntheticCrystallinityCrystallineChemistryComments
Alexandrite-synthetic optical propertiesTransparencyTransparent - TranslucentDispersionStrength: weak fire Value: 0.015OpticalCommentsRefractiveIndex1.746-1.755
Tolerance:(+0.004/-0.006)Birefringence0.008-0.01OpticCharacterBiaxialOpticSignPositivePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: Moderate to strong red
LWUV: Moderate to strong redCCFReactionNAPleochroismTrichroic, strong green, orange, and purplish red
Alexandrite-synthetic characteristic physical propertiesHardness8.5CharacteristicCommentsStreakWhiteSpecificGravity3.71-3.75 Range:+/- 0.02 Typical:3.73ToughnessVariesInclusionsFlux grown synthetic alexandrite might have metallic platelets from the platinum crucible, veil like inclusions, flux inclusions, flux filled cavities, straight or angular growth lines layers of dust-like inclusions parallel to seed plate.Czochralski method pulled stones will have needle like inclusions, curved striae and small black like gas bubbles.Floating zone or hydrothermal stones will have dark gas bubbles, long flat liquid inclusion and a swirled appearance.LusterBright VitreousStabilityVery GoodFractureConchoidalCleavageGood, in one direction