Sugilite Gemstone & Information | Gemopedia by JTV | Gemopedia™
Sugilite belongs to a class of minerals known as silicates and is a member of the milarite group. A relatively recent addition to the realm of gemstones, sugilite was discovered in 1944 by a Japanese geologist, Ken-ichi Sugi. The mineral is named in his honor. The original find was a yellowish brown variety that was of no interest to the jewelry industry. It was not until 1979 that the first massive aggregates, exhibiting a rich purple color, were discovered in a South African manganese mine. This material was attractive and gained the attention of the gemstone industry. It is predominantly found in the form of cabochons of various shapes and sizes, but has also been used as a component in intarsia jewelry. It is sometimes carved into decorative objects and fashioned into beads.
Red-Purple To Bluish Purple, Rarely Pink
Sugilite classificationCommonNameSugiliteSpeciesSugiliteVarietyColorsRed-Purple To Bluish Purple, Rarely PinkAlternateNamesRoyal Azel, Royal LavuliteGemstoneGroupsKeySeparationsIntense purplish color, RI, spectrum and SGClassificationCommentsMight show RI of 1.54 due to quartz impurities Misnomer: purple turquoise
Sugilite chemistry & crystallographyChemicalNamepotassium sodium lithium iron manganese silicateChemicalFormula(K,NA)(Na,Fe)2(Li2Fe)Si12O30SynthesisCrystalSystemHexagonalChemistryClassificationSilicateNatureNaturalCrystallinityCrystalline to AggregateChemistryComments
Sugilite optical propertiesTransparencySemitransparent - OpaqueDispersionOpticalCommentsRefractiveIndex1.607-1.61
Tolerance:(+0.001/-0.002)Birefringence0.003OpticCharacterUniaxialOpticSignNegativePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: Inert
Sugilite characteristic physical propertiesHardness5.5-6.5CharacteristicCommentsStreakWhiteSpecificGravity2.69-2.79 Typical:2.74ToughnessGoodInclusionsSugilite might have banded appearance.LusterVitreousStabilityFractureGranularCleavageNone