Pyrite

Pyrite or Iron Pyrites is Iron Sulfide mineral, it has an metallic gold luster.  This crystal is known to many as Fools Gold. 

In renaissance times hundreds of tons of Pyrite were shipped from the new world in the mistaken belief that it was actually Gold. Ironically small quantities of actual gold are sometimes found in pyrite.

Found all over the world but good specimens from Italy Spain and Peru.