Tanzanite is a type of zoisite and wasn't found until 1967, when a deposit was uncovered in Tanzania. This is still the only source for tanzanite and one of the most recent additions to the gem world. It gained almost immediate popularity both for its scarcity and its rich, blue-violet color. Tanzanite is often heat-treated to bring out a uniform color. Caution should be used when it is worn in rings, since it is fairly soft and can be scratched or chipped. Although it usually has good clarity, tanzanite can be damaged by ultrasonic cleaners, so other cleaning methods are recommended.
As a birthstone, tanzanite can be used for the month of December in place of blue topaz and turquoise.
||Pale to deep violet and blue
||Crystal of zoisite, a mineral formed of silicon, calcium and aluminum. Has a relatively soft Mohs' hardness rating of 6.