Tsavorite

Most people picture garnet as a deep wine red. Tsavorite is a garnet too, and it is green: a clear, bright green that at its best is an intense green to blue-green, and can be mistaken for emerald. The Smithsonian calls it one of the rarest and most prized garnets today.

Tsavorite is not South African. It is an East African gem, and like tanzanite it is young: it was first found in 1967. If you have come to the Garden Route from a safari further north, this is the gem of that country.

A geologist and a safari park

Tsavorite was found in 1967 in northern Tanzania, and again in 1970 in Kenya's Tsavo National Park, both times by the geologist Campbell Bridges. In 1973 he and Henry Platt, then president of Tiffany & Co., named it in honour of Tsavo, and in 1974 Tiffany launched it to the world. The region along the Kenya–Tanzania border is still almost the only source of gem tsavorite.

What it is

Tsavorite is the green variety of grossular, one member of the garnet family. Its green comes from traces of vanadium and chromium, the same elements that colour emerald.

Treatments, honestly

Tsavorite is not heated, oiled, filled or treated in any other way. The colour you see is the colour it came out of the ground with.

How to judge a tsavorite

• Colour first: the most valued is an intense green to blue-green.
• Size matters a great deal. Clean tsavorites over a carat are rare, and above about two carats the price per carat jumps sharply.
• Clarity: look for a stone that is clean to the eye.

Caring for your tsavorite

Tsavorite is 7 to 7.5 on the Mohs scale, hard enough for everyday wear, but a garnet can chip from a hard knock. Clean it in warm soapy water with a soft brush; avoid steam, and ultrasonic cleaning if the stone has inclusions. Store it apart from harder gems such as diamond and sapphire.

At a glance