Color Change Sapphire Gemstone & Information | Gemopedia by JTV | Gemopedia™
While color change sapphires come from a variety of locations, the gem gravels of Tanzania are the main source. Color change sapphires present gem lovers with an opportunity to own the rare and stunning color change effect in a gem other than alexandrite, garnet, spinel, tourmaline or diaspore. While the colors tend to vary depending on locale, in general they change from blue to purple. You can observe color change in this gem by viewing it interchangeably in natural and incandescent light.
Pink-Brown Through Brownish Pink, Purple Changing To Yellowish Brown, Grayish Violet, Grayish Blue, Green
Color-change-sapphire classificationCommonNameColor Change SapphireSpeciesCorundumVarietyColor Change SapphireColorsPink-Brown Through Brownish Pink, Purple Changing To Yellowish Brown, Grayish Violet, Grayish Blue, GreenAlternateNamesGemstoneGroupsKeySeparationsRI, birefringence, magnification and color changeClassificationCommentsWill have a spectra similar to ruby and pink sapphire.
Color-change-sapphire chemistry & crystallographyChemicalNamealuminum oxideChemicalFormulaAl2O3SynthesisCrystalSystemTrigonalChemistryClassificationOxideNatureNaturalCrystallinityCrystallineChemistryComments
Color-change-sapphire optical propertiesTransparencyTransparent - SemitranslucentDispersionStrength: weak fire Value: 0.018OpticalCommentsRefractiveIndex1.762-1.77
Tolerance:(+0.009/-0.005)Birefringence0.008-0.01OpticCharacterUniaxialOpticSignNegativePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: Inert
LWUV: InertCCFReactionPleochroismDichroic, varies with bodycolor
Color-change-sapphire characteristic physical propertiesHardness9CharacteristicCommentsStreakWhiteSpecificGravity4.1-3.95 Typical:4ToughnessExcellentInclusionsThis stone has a type II clarity. Color change sapphire sometimes have silk composed of rutile needles, dark brown crystals, boehmite or zircon crystals. Stones might have fingerprint or 2-phase inclusions. Hexagonal growth and strong color zoning are possible in some stones. Untreated stones will usually have inclusions intact. Heat treated stones will have fracture halos or snowballs around crystal inclusions(untreated stones from magmatic areas might also show these characteristics). Silk will be broken and might show sintered areas especially around the girdle.LusterSubAdamantineStabilityVery GoodFractureConchoidalCleavageNone