The name tanzanite (after the East African state of Tanzania) was introduced by the New York jewellers Tiffany & Co.

It is accepted by the trade. Although scientists do not encourage a multitude of gemstones and refer to it as blue zoisite.

Details:

In good quality the color is ultramarine to sapphire blue, in artificial light, more amethyst violet.
When heated the yellow and brown tints vanish, and the blue deepens. Tanzanite cat’s eyes are also found.
Some deposits in Tanzania near Arrusha occur in veins or filling of fissures of gemstones.

*Info by Walter Schumann “Gemstones of the World”