16.14.03: Bi-color
- Page ID
- 4344
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| Bi-color Tourmaline | |
|---|---|
| Chemical composition | Complex borosilicate |
| Crystal system | Trigonal |
| Habit | Prismatic |
| Cleavage | None |
| Fracture | Conchoidal |
| Hardness | 7- 7.5 |
| Optic nature | Uniaxial - |
| Refractive index | 1.62 - 1.64 |
| Birefringence | 0.014 - 0.040 |
| Dispersion | Low, 0.017 |
| Specific gravity | 3.01 - 3.11 |
| Lustre | Vitreous |
| Pleochroism | Strong |
Figure \(\PageIndex{1}\): Bi-color tourmaline
Photo courtesy of Lembeck Gems