Main centres: | 1-3 business days |
Regional areas: | 3-4 business days |
Remote areas: | 3-5 business days |
Tanzanite 91 carats.
will heat treat to a medium blue/purple color.
Tanzanite is the blue/purple variety of the mineral zoisite discovered in the Meralani (Merelani) Hills (Merelani) of northern Tanzania in 1967, near the city of Arusha. It is a popular and valuable gemstone when cut, although its durability is somewhat lacking; its tendency to break sometimes precludes appropriate use as a ring stone. Tanzanite is noted for its remarkably strong trichroism, appearing alternately sapphire blue, violet, and sage-green depending on crystal orientation. However most tanzanite is subjected to artificial heat treatment to improve its colour, and this significantly subdues its trichr
General | |
---|---|
Category | Mineral Variety |
Chemical formula | (Ca2Al3(SiO4)(Si2O7)O(OH)) |
Identification | |
Color | Purple to Blue |
Crystal habit | Crystals flattened in an acicular manner, may be fibrously curved |
Crystal system | Orthorhombic |
Cleavage | Perfect {010} imperfect {100} |
Fracture | Uneven to conchoidal |
Mohs Scale hardness | 6.5 |
Luster | Vitreous, pearly on cleavage surfaces |
Refractive index | 1.69-1.70 |
Optical Properties | biaxial positive |
Birefringence | 0.006-0.018 |
Pleochroism | Present, dichroism or trichroism depending on color. |
Streak | White or colorless |
Specific gravity | 3.10-3.38 |
91 ct Stunning Stone!!