Thulite
From The Gemology Project
| Thulite | |
|---|---|
| Chemical composition | Calcium aluminum silicate |
| Crystal system | Orthorhombic |
| Habit | Massive |
| Hardness | 6.5 |
| Optic nature | Biaxial + |
| Refractive index | 1.685-1.707 |
| Birefringence | 0.008 |
| Dispersion | Low, 0.012 |
| Specific gravity | 3.35 |
| Lustre | Vitreous |
