Property |
Specification |
Chemical Composition |
Sodium aluminum silicate with sulfur (Na8(Al6Si6O24)S2) |
Color |
Deep blue, with golden pyrite inclusions |
Hardness |
5 to 5.5 on the Mohs scale |
Specific Gravity |
2.7 to 2.9 g/cm³ |
Transparency |
Opaque |
Luster |
Vitreous to sub-metallic |
Texture |
Rough, uneven, often granular |
Crystal Structure |
Massive, granular, occasionally columnar |
Cleavage |
None |
Fracture |
Conchoidal |
Density |
2.7 – 2.9 g/cm³ |
Refractive Index |
1.5 to 1.7 |
Streak |
Pale blue to white |
Associated Minerals |
Pyrite, Calcite, and other minerals |
Origin |
Afghanistan, Chile, Russia, USA, and others |
Uses |
Jewelry, carvings, ornamental stones |