Template:Heliodor
From The Gemology Project
Heliodor | |
---|---|
Chemical composition | Beryllium Aluminium Silicate Be3Al2(SiO3)6 |
Crystal system | Hexagonal |
Habit | prismatice |
Cleavage | poor, basal |
Fracture | conchoidal to uneven |
Hardness | 7.5 |
Optic nature | uniaxial - |
Refraction index | 1.57 - 1.58 |
Birefringence | 0.004 - 0.009 |
Dispersion | low, 0.014 |
Specific gravity | 2.7 - 2.9 |
Lustre | Vitreous |
Pleochroism | weak to moderate (shades of body color) |