Lazurite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameLazurite
Chemical Formula(Na,Ca)8(Al6Si6O24)(S,SO4,Cl)2
Mohs Hardness5
Crystal Systemcubic
Lustervitreous
Streak Colorlight blue to white
Cleavagedistinct on {110} (dodecahedral), but often poor
Fractureuneven to conchoidal
Specific Gravity2.4
Colorsdeep blue, royal blue, violet-blue
Transparencytranslucent to opaque
Type LocalitySar-e-Sang District, Koksha Valley (Kokscha; Kokcha), Badakhshan (Badakshan; Badahsan) Province, Afghanistan
Mineral GroupSilicates
Usesgemstone, ornamental, pigment
Associated Mineralscalcite, pyrite, diopside, afghanite
Rarityuncommon
Description
This specimen showcases vibrant deep blue lazurite crystals, some exhibiting dodecahedral forms, embedded within a white calcite matrix and accented by scattered golden pyrite inclusions.
Geological Context
Lazurite typically forms in metamorphosed limestones or marbles, often as a result of contact metamorphism, where it replaces carbonate minerals in skarn deposits.
