Danburite Gemstone & Information | Gemopedia by JTV | Gemopedia™
In 1839 American mineralogist Charles Upham Shephard discovered a clear, bright, colorless gemstone in Danbury, Connecticut, and named it danburite after the location. Unfortunately for danburite, it was discovered at a time when colored gemstones were heavily promoted and highly desired. This colorless find, therefore, didn't create much excitement at that time. Danburite, which belongs to a class of minerals known as silicates, remained relatively unknown for years, but is steadily growing in popularity today.
Colorless, Light Yellow To Brown, Light Pink
Danburite classificationCommonNameDanburiteSpeciesDanburiteVarietyColorsColorless, Light Yellow To Brown, Light PinkAlternateNamesGemstoneGroupsKeySeparationsRI, birefringence, optic character and SG. Biaxial positive or negative with the common point halfway between highest RI and lowest RI.ClassificationCommentsDanburite can be chatoyant if it has parallel growth tubes.
Danburite chemistry & crystallographyChemicalNamecalcium boron silicateChemicalFormulaCaB2(SiO4)2SynthesisCrystalSystemOrthorhombicChemistryClassificationSilicateNatureNaturalCrystallinityCrystallineChemistryComments
Danburite optical propertiesTransparencyTransparent - TranslucentDispersionStrength: weak fire Value: 0.016OpticalCommentsRefractiveIndex1.63-1.636
Tolerance:(+0.003/-0.003)Birefringence0.006OpticCharacterBiaxialOpticSignPositive or NegativePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: inert to weaker, light blue to blue-green
LWUV: inert to strong, light blue to blue-greenCCFReactionPleochroismDichroic, unobservable or weak, varying shades of body color
Danburite characteristic physical propertiesHardness7CharacteristicCommentsStreakWhiteSpecificGravity2.97-3.03 Typical:3ToughnessGoodInclusionsDanburite might have natural inclusions, fingerprints and parallel growth tubes.LusterVitreousStabilityFractureUneven, SubconchoidalCleavageNone