Tanzanite is a blue-violet gemstone found in only one place in the world: a small area of hills at Mererani, between Arusha and Kilimanjaro. Its rarity and colour have made it one of the most popular gems of the last 50 years.
Discovery
Tanzanite was identified in 1967, when a Maasai herder and a local prospector found blue crystals in the Mererani hills. The New York jeweller Tiffany & Co. launched it worldwide in 1968 and named it after Tanzania. Mineralogically, it is a blue variety of zoisite.
Colour
Tanzanite shows different colours from different angles, from blue to violet to burgundy. Most stones are gently heated after mining to bring out the blue-violet colour. This is standard practice and permanent.
How quality is judged
| Factor | What to look for |
|---|---|
| Colour | Deep, saturated blue-violet is most valuable |
| Clarity | Eye-clean stones without visible inclusions |
| Cut | Even shine without dark or washed-out areas |
| Carat | Larger stones with good colour are rare |
Buying tanzanite safely
- Buy from established, certified dealers in Arusha or reputable jewellers.
- Ask for a certificate stating the stone’s details and a receipt for customs.
- Avoid street sellers. Glass and other stones are often sold as tanzanite. Read common scams in Tanzania.
- Tanzanite is relatively soft, so choose settings that protect the stone.
Learn more in Arusha
Museums and showrooms in Arusha explain the geology and mining, and show stones at every stage from rough to cut. Read souvenirs from Tanzania.
Frequently asked questions
Only in the Mererani hills between Arusha and Kilimanjaro in northern Tanzania.
In 1967. Tiffany & Co. launched and named it in 1968.
Most tanzanite is gently heated to bring out its blue-violet colour. This is normal and permanent.
