Property |
Specification |
Chemical Formula |
(Na, Ca)(Al, Fe, Mg, Li)3(Al, Cr, V)6(Si6O18)(BO3)3(OH)4 |
Color |
Ranges from pink, green, blue, to multi-colored (bicolored, tricolored) |
Crystal System |
Hexagonal (Trigonal) |
Hardness |
7 to 7.5 on the Mohs scale |
Specific Gravity |
3.06 to 3.24 |
Refractive Index |
1.62 to 1.64 |
Density |
2.9 to 3.2 g/cm³ |
Cleavage |
None (fracture is irregular or conchoidal) |
Transparency |
Transparent to opaque |
Luster |
Vitreous (glassy) to sub-adamantine |
Fracture |
Uneven or conchoidal |
Occurrence |
Found in metamorphic rocks, granites, and pegmatites |
Inclusions |
Often contains inclusions like rutile, gas bubbles, or minerals |
Common Shapes |
Rough chunks, elongated crystals, or irregular fragments |
Size |
Varies from small grains to large boulders |