Tanzanite is the blue purple variety of the mineral Zoisite discovered in the Merani Hills in Northern Tanzania in 1967. Tanzanite is a gemstone which, naturally formed, is extremely rare. Tanzanite is usually a reddish brown in its rough state, requiring artificial heat treatment to bring out the blue violet of the stone. Since heat treatment is universal, it has no effect on price, and finished goods are assumed to be heat treated. Gemological Institute of America states that the source of heating is gemologically undetectable, but is assumed because of its prevalence.
Photo Credit: Yuli
The mineral was named by Tiffany & Co. after Tanzania, the country in which it was discovered. The American Gem Trade Association chose tanzanite as one of the December birthstones.1