Dioptase
From The Gemology Project
| Dioptase | |
|---|---|
| Chemical composition | CuSiO3H2O |
| Crystal system | Trigonal |
| Habit | Prismatic |
| Cleavage | Perfect, rhombohedral |
| Fracture | Conchoidal to uneven |
| Hardness | 5 |
| Optic nature | Uniaxial + |
| Refractive index | 1.644 - 1.709 |
| Birefringence | 0.053 |
| Dispersion | Medium, 0.030 |
| Specific gravity | 3.28 - 3.35 |
| Lustre | Vitreous |
| Pleochroism | Weak |
