Template:Iolite
From The Gemology Project
Iolite | |
---|---|
Chemical composition | Complex Mg-Al (magnesium aluminum) silicate |
Crystal system | Orthorhombic |
Habit | Massive, prisms |
Cleavage | Distinct, basal |
Fracture | Sub-conchoidal |
Hardness | 7.5 |
Optic nature | Biaxial - |
Refractive index | 1.53 - 1.55 |
Birefringence | 0.008 - 0.012 |
Dispersion | Low, 0.017 |
Specific gravity | 2.58 - 2.74 |
Lustre | Vitreous |
Pleochroism | Strongly trichroic |