Sphalerite is a zinc sulfide mineral with the chemical formula ZnS. It is the most common ore of zinc and is also known as blende or blackjack. Sphalerite has perfect cleavage in six direction, meaning that it can be easily split along these planes to form smooth surfaces. This property is due to the mineral's crystal structure, which is cubic. Diamond, fluorite, and sodalite do not have perfect cleavage in six direction.