Pyrite

Pyrite has been confused with gold since the beginning of time, hence the nickname "Fool's Gold." Actually it is a compound composed of iron and sulfur and is a common mineral in many ore bodies. Its name comes from the Greek pyr, meaning "fire", because becuase it produces sparks when struck by iron. Among the several shapes that pyrite may occur as are cubes, dodecahedrons, and dipyraminds.