Heliodor
From The Gemology Project
Revision as of 23:50, 13 September 2006 by Africanuck (talk | contribs)
Heliodor | |
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Chemical composition | Be3Al2(SiO3)6 Beryllium aluminum silicate |
Crystal system | Hexagonal |
Habit | Prismatic |
Cleavage | Poor, basal |
Fracture | Conchoidal to uneven |
Hardness | 7.5 |
Optic nature | Uniaxial - |
Refractive 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) |