Small levels of vanadium form tanzanite, a blue and violet variation of the mineral zoisite (a calcium aluminum hydroxyl sorosilicate). Tanzanite is a mineral that belongs to the epidote family. Tanzanite is exclusively discovered in Tanzania, near the Mererani Hills, in a limited mining region.
Tanzanite is known for its unusually intense trichroism, which can seem blue, violet, or burgundy depending on the crystal orientation. When viewed in different lighting conditions, Tanzanite can also appear differently. When viewed under fluorescent light, the blues are more visible, while when viewed in incandescent light, the violet colors are more visible. Tanzanite is colored a reddish brown to clear in its natural condition, and it requires heat treatment to remove the brownish "veil" and reveal the stone's blue violet color.
Tiffany & Co. gave the gemstone the name tanzanite after Tanzania, the nation where it was discovered. Tiffany's marketing staff did not think the scientific name of "blue-violet zoisite" was consumer friendly enough when it first released it to the market in 1968. The American Gem Trade Association chose tanzanite as the December birthstone in 2002, the first time the list had been updated since 1912.
