| Property |
Specification |
| Chemical Formula |
Be₃Al₂(SiO₃)₆ (Beryllium Aluminum Silicate) |
| Crystal System |
Hexagonal |
| Crystal Habit |
Prismatic crystals, columnar |
| Color |
Pale blue to blue-green |
| Streak |
White |
| Luster |
Vitreous (glassy) |
| Transparency |
Transparent to translucent |
| Hardness (Mohs scale) |
7.5 - 8 |
| Specific Gravity |
2.68 - 2.74 |
| Cleavage |
Poor, indistinct |
| Fracture |
Conchoidal to uneven |
| Refractive Index |
1.577 - 1.583 |
| Birefringence |
0.004 - 0.009 |
| Optical Properties |
Uniaxial (+) |
| Pleochroism |
Yes, blue to greenish-blue |
| Melting Point |
~1,650 °C (estimated, decomposes before melting) |
