Iron pyrite is found almost everywhere, and certainly turns up often in Arizona. Much of our Arizona history is about mining, and many a mining enthusiast and rock collector has great samples of fool’s gold. It is also called marcasite when mixed with silver. Although sometimes mistaken for gold, it is very different. Gold is made up of only gold atoms, while pyrite is a combination of iron and sulphur atoms. It is pretty easy to distinguish the two. Pyrite is not as dense, is harder, and has a different color than gold. Gold weighs about one and a half times the weight of pyrite.Pyrite is very common, and so is not valuable, except as a pretty collector’s item.