Prosopite Gemstone & Information | Gemopedia by JTV | Gemopedia™
The mineral prosopite is named from the Greek word prosopon, meaning mask, most likely a reference to its pseudomorphic forms. It typically ranges in color from white to gray to colorless. There is a beautiful blue Mexican variety that resembles softly colored turquoise that is of particular interest to collectors.
Colors
Robin's Egg Blue, Colorless To Grayish White
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Prosopite classification
CommonNameProsopiteSpeciesProsopiteVarietyColorsRobin's Egg Blue, Colorless To Grayish WhiteAlternateNamesGemstoneGroupsKeySeparationsRI, SG and possibly specrtumClassificationComments -
Prosopite chemistry & crystallography
ChemicalNamecalcium aluminum flouride hydroxideChemicalFormulaCaAl2(F,OH)8SynthesisCrystalSystemMonoclinicChemistryClassificationHalideNatureNaturalCrystallinityAggregateChemistryComments -
Prosopite optical properties
TransparencyTransparent - OpaqueDispersionStrength: noneOpticalCommentsRefractiveIndex1.501-1.51Birefringence0.009OpticCharacterBiaxialOpticSignPositivePolariscopeReactionDoubly Refractive (DR)FluorescenceSWUV: Inert
LWUV: InertCCFReactionPleochroismUnobservable -
Prosopite characteristic physical properties
Hardness4.5CharacteristicCommentsStreakSpecificGravity2.69-2.9 Typical:2.88ToughnessFairInclusionsLusterVitreousStabilityFractureConchoidal, UnevenCleavagePerfect, in one direction