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Precious stones
Semi-precious stones
Technical information
History of the stones
Characteristics :
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 : Round  Emerald  Cabochon  Marquise  Pear
Tanzanite name wasn't approved unanimously by the gemmologists who consider it as blue zoisite !.

History :
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 !