Andalusite
From The Gemology Project
Revision as of 01:35, 14 September 2006 by Africanuck (talk | contribs)
Andalusite | |
---|---|
Chemical composition | Al2SiO5 |
Crystal system | Orthorhombic |
Habit | Prismatic |
Cleavage | Distinct |
Fracture | Sub-conchoidal |
Hardness | 7.5 |
Optic nature | Biaxial - |
Refractive index | 1.63-1.64 |
Birefringence | 0.010 |
Dispersion | Low, 0.016 |
Specific gravity | 3.18 |
Lustre | Vitreous |
Pleochroism | Very strong |