Tourmalines
VIBRANIUM LTD
Tourmalines
| Property | Specification |
| Chemical Formula | (Na,Ca)(Li,Mg,Al,Fe)?Al?(BO?)?Si?O??(OH,F)? |
| Crystal System | Hexagonal (Trigonal) |
| Color | Wide range: Yellow, Brown, Watermelon (bi-colored) |
| Hardness (Mohs) | 7 - 7.5 |
| Specific Gravity | 2.82 - 3.32 |
| Refractive Index | 1.614 - 1.666 |
| Birefringence | 0.014 - 0.040 |
| Luster | Vitreous |
| Transparency | Transparent to Opaque |
| Pleochroism | Moderate to Strong (color varies with viewing angle) |
| Optical Character | Uniaxial (-) |
| Dispersion | 0.017 |
| Cleavage | Indistinct |
| Fracture | Conchoidal to Uneven |
| UV Fluorescence | Weak to None (varies by variety) |