Tanzanite is one of the best-selling colored stones in today’s gem and jewelry markets. That is a surprise considering that it was only discovered in the 1960s, while all of the other best-selling colored stones have been known for centuries. It has a unique blue color that grows in popularity as more people learn about it. The popularity is expected to grow as colored stones become more common purchases in developing economies.

At the same time, tanzanite is a rare gem. All of the known deposits are confined to a few square miles of land in northern Tanzania. It is the only gemstone with a large and growing popularity that has such a limited known supply. Some people believe that the currently known tanzanite resource could be depleted in just a few decades.

A study, published in 2018 by the National Bureau of Statistics of Tanzania, estimated that the total tanzanite reserves were 109 million carats. [6] Also in 2018, the High Commission of the United Republic of Tanzania, reported that Block C, the largest block in the tanzanite mining area, accounting for over 50% of the mining area, and the only mechanized block, had estimated total reserves of about 87.1 million carats. These reserves were thought to be enough to support mining into the 2040s.

These reports are for the current tanzanite mining area. They do not consider discoveries that might be made in other parts of Tanzania, or in other parts of the world.

Tanzanite with graphite and laumontite: Crystals of blue tanzanite in a rock matrix with graphite and laumontite. Specimen is from Merelani Hills, Tanzania.