Template:Corundum
From The Gemology Project
Corundum | |
---|---|
Chemical composition | Al2O3 |
Crystal system | trigonal |
Habit | prismatic, tabular |
Cleavage | poor |
Fracture | conchoidal |
Hardness | 9 |
Optic nature | uniaxial - |
Refaction index | 1.76-1.78 |
Birefringence | 0.008-0.009 |
Dispersion | low, 0.018 |
Specific gravity | 4 |
Lustre | bright vitreous |
Pleochroism | weak to moderate |