.8" Tanzanite Crystals, Calcite and Graphite Association - Tanzania

Tanzanite is a blue-violet variety of zoisite that gains its color from the substitution of vanadium within the zoisite mineral structure. It is found only in the Arusha and Manyara regions of Tanzania, Africa, which it is named after. It is well known and relatively popular in the gemstone community for its lovely color and pleochroic effect when viewing from different angles. That pleochroism is taken into account prior to faceting into a gemstone to ensure it is cut at an angle that delivers the strongest blue-violet color. Tanzanite is relatively soft for a gemstone, however, so its uses in jewelry are somewhat limited.

Zoisite belongs to the epidote group of minerals and its chemical formula is Ca2Al3(SiO4)(Si2O7)O(OH) (calcium aluminium hydroxy sorosilicate). It can be found in a variety of colors including green, pink, brown, yellow, grey, white, blue, purple, or colorless. The color it bears is dependent on the ion substitutions within the crystal lattice: for example, thulite is a pink variety of zoisite that gains its pink color from manganese substituting calcium within the crystal lattice.

Zoisite was originally known as saualpite.