Tanzanite is only found in one place in the entire world, in the foothills of Mt. Kilimanjaro. It is commonly thought that tanzanite was discovered in 1967 by a Maasai tribesman. The tribesman found a transluscent blue rock that he thought to be a sapphire. When the stone was tested, it was found to have different properties than corundum (sapphire). What the tribesman had found was determined to be the crystalline form of the mineral zoisite.
Mined with very primitive methods, most tanzanite crystals come out of the ground demonstrating a dingey yellowish-brown color. Through heat treatment at 500+ degrees celcius the rough tanzanite crystals turn their beautiful purplish-blue color. The rough tanzanite gems are then faceted into various shapes in India, USA and Europe and then marketed to dealers who wholesale the finished gems to jewelry manufacturers and retailers.
Tanzanite colors occur in various shades of gray, brown, violet, blue, reddish-purple, and tints of green.