Fool's Gold

Today’s choice of a blip photo for the Tuesday challenge  minerals could not have been easier. I just had to find something in M’s store of rocks gathered mostly from his Open University geology expeditions.
He bought this piece of Fools gold for about £6 from the Rock Store adjoining the meteor crater in Arizona.
 
For the technically minded “Fool's Gold” is known as pyrite or iron sulfide (FeS2) and is one of the most common sulfide minerals.