Imperial Topaz Gemstone & Information | Gemopedia by JTV | Gemopedia™
At the height of Imperial Russia's power, orange-pink topaz was brought from Brazil to decorate the jewelry of the Tzarina. Since then, these colors have been known as imperial topaz, and still today remains one of the most coveted topaz varieties. Interestingly enough, some sources dispute this legend and state that imperial topaz was indeed named in honor of the Brazilian ruler in power at the time, Emperor Don Pedro. Classified as a rare collector's gem, the world's supply of imperial topaz comes from sources in the Brazilian state of Minas Gerais. It is generally the reddish-orange or orange-red variety of topaz that's considered "imperial." Some also consider yellowish-orange, cognac-colored and pure orange to be imperial topaz.
Fine Medium Reddish Orange, Orange Red
Imperial-topaz classificationCommonNameImperial TopazSpeciesTopazVarietyImperial TopazColorsFine Medium Reddish Orange, Orange RedAlternateNamesGemstoneGroupsKeySeparationsrefractive index, birefringence, optic character; possibly specific gravity.ClassificationCommentsBiaxial positive common point is 0.001 from low RITopaz can have an RI of 1.619 to 1.627 (+0.010/-0.010).
Imperial-topaz chemistry & crystallographyChemicalNamealuminium silicate fluoride hydroxideChemicalFormulaAl2(F,OH)2SiO4SynthesisCrystalSystemOrthorhombicChemistryClassificationSilicateNatureNaturalCrystallinityCrystallineChemistryComments
Imperial-topaz optical propertiesTransparencyTransparentDispersionStrength: weak fire Value: 0.014OpticalCommentsRefractiveIndex1.629-1.637Birefringence0.008-0.01OpticCharacterBiaxialOpticSignPositivePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: inert to weak greenish white
LWUV: inert to moderate orange or yellowCCFReactionPleochroismDichroic, weak to moderate light red and orangy red to yellow
Imperial-topaz characteristic physical propertiesHardness8CharacteristicCommentsStreakWhiteSpecificGravity3.49-3.57 Typical:3.53ToughnessGoodInclusionsImperial topaz is a type II clarity stone. Stones sometimes contain long tube-like cavities containing liquid, healed fractures and areas that look like they are starting to cleave. Stones might include 2-phase and 3-phase inclusions some of which contain more than one liquid that have not been mixed.LusterVitreousStabilityFairFractureConchoidalCleavagePerfect, in one direction