Tanzanite

A precious gemstone from the zoisite family. Colors naturally occur in shades of blue, green, yellow, pink, brown, and khaki, but virtually all gemstone quality crystals are heat treated to produce the popular shades of sapphire blue, amethyst, and blue violet. On Mohs' scale of hardness, tanzanite is 6.5-7. Named for the stone's prime mining source: Tanzania.