Have you heard of Fool’s Gold?  It is a stone that looks like gold, but it is not gold at all.  Fool’s gold has made a fool out of many a treasure hunter looking to strike it rich.  Fool’s Gold is Pyrite.  Pyrite is a mineral composed of iron sulfide.  This mineral forms a cubic structure and has a brassy, golden metallic color that makes it look just like gold.

Look at how similar the Pyrite image above is to the picture of a gold nugget shown below.