Tsavorite

Tsavorite is a vivid green grossular garnet whose brilliant, emerald-like color is caused by vanadium and chromium. Its name was coined by the gemologist Campbell Bridges and Tiffany & Co. after Tsavo National Park in Kenya, near the site of its 1967 discovery. The gem requires no treatment to achieve its natural green and possesses a higher refractive index than emerald, giving faceted stones superior brilliance. The finest tsavorites, from Kenya and Tanzania, rival the best Colombian emeralds in color saturation. With a Mohs hardness of 7 to 7.5 and good toughness, tsavorite is well suited to everyday jewelry. It crystallizes in the isometric system with a refractive index near 1.74, and because it is rarely found in large sizes, faceted stones above a few carats are especially valuable.