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 Tanzanite |
| Crystal structure : Orthorhombic |
Composition : Calcium and aluminium silicate |
| Specific gravity : 3.35 |
Hardness : 6.5-7 |
| Refractive index : 1.691-1.700 |
Birefringence : 0.009 |
| Variety : Zoisite |
Pleochroïsm : very strong (purple, blue, brown) |
Cut :      |
| Tanzanite name wasn't approved unanimously by the gemmologists who consider it as blue zoisite !. |
Tanzanite takes one's name from Tanzania.
The coast of this stone is soaring up during the collapse of the main mine in Tanzania. |
| Deposits : |
| Only one country of course : Tanzania ! |
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