A blue bonanza

Discovered in Tanzania during the 1960s, tanzanite is a gemstone belonging to the ‘zoisite’ family. It’s also known as ‘blue zoisite’.

When cut and polished, the gemstone is a lustrous blue or purple. Its crystal Tanzanite, by Beckstet (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commonsappearance means it’s regularly used in jewellry as an alternative to sapphires. But because it’s relatively soft, the stone is normally set into a necklace or earrings.

In its natural rough state, this gemstone is actually a reddish-brown. It has to be heated artificially in a furnace at around 600 degrees Celsius to acquire its blue/violet colouring.

It was first found near the city of Arusha, in the Mount Kilimanjaro region (see Map), and is still mined in the foothills today. The mining and production of tanzanite earns the country around 20 million dollars each year.