Tsavorite garnet is the green variety of grossular garnet and gets its colour from trace impurities of vanadium and sometimes chromium. It was named by Tiffany & Co. after the Tsavo National Park in southeast Kenya where it was first discovered in 1968. It is a relatively rare stone with intense medium-green colouring and larger eye clean gems are very rare. It is not normally subject to any type of treatment or enhancement. Hardness: 7 (Mohs).