Its chemical formula may therefore be written …The main zinc mineral is sphalerite ((Zn,Fe)S), which contains up to 67% zinc by mass. It is characterized by single bonds between each atom and maintenance of a 1:1 zinc to sulfur ratio.Sphalerite is a mineral that consists largely of zinc sulfide in crystalline form, but it almost always contains variable amounts of iron. Wurtzite has a hexagonal structure, while zincblende is cubic. These two polymorphs are wurtzite and zincblende (also known as sphalerite). Zinc sulfide (ZnS) is a unique compound that forms two types of crystalline structures.
