Thulite Gemstone & Information | Gemopedia by JTV | Gemopedia™
Thulite is the translucent to opaque pink variety of zoisite, which is often mottled or streaked with gray or white quartz. The name thulite is derived from its discovery location, Norway, which was once called Thule. This gem is also called rosaline. Thulite is often cut en cabochon for jewelry manufacture or carved into ornaments.
Pink To Red, Often With Mottled, Streaked With Gray, White
Thulite classificationCommonNameThuliteSpeciesZoisiteVarietyThuliteColorsPink To Red, Often With Mottled, Streaked With Gray, WhiteAlternateNamesRosaline, UnioniteGemstoneGroupsEpidoteKeySeparationsrefractive index, appearance and SGClassificationCommentsNational gemstone of Norway. RI might be as low as mid 1.50s due to impurities
Thulite chemistry & crystallographyChemicalNamecalcium aluminum silicate hydroxideChemicalFormulaCa2Al3(SiO4)3(OH)SynthesisCrystalSystemOrthorhombicChemistryClassificationSilicateNatureNaturalCrystallinityCrystalline to AggregateChemistryComments
Thulite optical propertiesTransparencyTranslucent - OpaqueDispersionStrength: weak fire Value: 0.021OpticalCommentsRefractiveIndex1.691-1.7
Tolerance:(+0.005/-0.005)Birefringence0.008-0.013OpticCharacterBiaxialOpticSignPositivePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: Inert
Thulite characteristic physical propertiesHardness6-7CharacteristicCommentsStreakWhiteSpecificGravity3.1-3.45 Typical:3.35ToughnessVariesInclusionsThulite has white veining is due to calcite and the pink color is due to manganese.LusterVitreousStabilityGoodFractureConchoidal, UnevenCleavagePerfect, in one direction, Good, in one direction