Tanzanite is the blue/purple variety of the mineral zoisite which was discovered in the Meralani (Merelani) Hills of Northern Tanzania in 1967, near the city of Arusha. It is used as a gemstone.
Tanzanite is noted for its remarkably strong trichroism, appearing alternately sapphire blue, violet, and burgundy depending on crystal orientation.
Tanzanite in its rough state is usually a reddish brown color.
It requires artificial heat treatment to 600 °C in a gemological oven to bring out the blue violet of the stone.
Tanzanite is a rare gem. It is found mostly in the foothills of Mount Kilimanjaro.
The mineral is named after Tanzania, the country where it was discovered.