Pyrite is more commonly known as fool's gold and is familiar to nearly every mineral collector. It has been used for centuries both in jewelry and as an ore of iron. “Marcasite” stones in jewelry are frequently pyrite, since the latter is more stable. The name "pyrite" is after the Greek "pyr" meaning "fire." This name was given because pyrite can be used to create the sparks needed for starting a fire if it is struck against metal or another hard material. Pieces of pyrite have also been used as a spark-producing material in flintlock firearms. The only common mineral that has properties similar to pyrite is marcasite, a dimorph of pyrite with the same chemical composition but an orthorhombic crystal structure. Marcasite does not have the same brassy yellow color of pyrite. Instead it is a pale brass color, sometimes with a slight tint of green.