Sodalite
From The Gemology Project
| Sodalite | |
|---|---|
| Chemical composition | Sodium aluminum silicate |
| Crystal system | Cubic |
| Habit | Massive |
| Cleavage | Distinct, dodecahedral |
| Fracture | Conchoidal to uneven |
| Hardness | 5.5-6.0 |
| Refractive index | 1.478-1.488 |
| Birefringence | None |
| Specific gravity | 2.27 |
| Lustre | Vitreous to greasy |
