Tsavorite

Tsavorite is the vivid green gem variety of grossular garnet, coloured by traces of vanadium and chromium. Discovered in East Africa in the late 1960s, it was named after Tsavo in Kenya and introduced to the trade by Tiffany & Co. Its bright green rivals emerald, with the advantage of greater durability and brilliance.

Properties

Like all garnets it is isometric, singly refractive, hard (7–7.5) and cleavage-free. Tsavorite is typically cleaner than emerald and has a higher refractive index, giving cut stones lively brilliance, though large clean crystals are rare so most faceted stones are small.

Occurrence

It forms in metamorphic rocks straddling the Kenya–Tanzania border. It is a member of the garnet group, alongside the green andradite variety demantoid.