Sphalerite (zinc iron sulphide), also known as zinc blende, is the chief ore of zinc. It consists largely of zinc sulphide in crystalline form but almost always contains variable amounts of iron. It is found as either isometric tetrahedral crystals or in compact crypotocrystalline masses. Zinc extraction from sphalerite also yields cadmium, gallium and indium. This sample is from Joplin, Missouri, USA.