Tanzanite came onto the market in the 1960s and is the purple blue variety of the mineral zoisite. The name Tanzanite was coined by Tiffany & Co. but has since come into common usage. Tanzanite comes from several mines in Tanzania's Great Rift Valley. It is America's second most popular gemstone after sapphire.

The popularity of Tanzanite is primarily because of the striking color and the ability to buy large stones for comparatively reasonable prices.

Color is the most important characteristic in determining Tanzanite's value but it is also important to consider the stone size, cut, and freedom from inclusions.

Virtually all Tanzanite has been heat treated to create the coloration. In fact, most natural zoisite crystals are gray in color and don't exhibit the distinctive coloration until they have been heat treated. This treatment is permanent under normal conditions and is not usually specifically disclosed to the consumer.

Tanzanite is now generally accepted as a birthstone for December along with Zircon and turquoise.