Iron Pyrite
Pyrite, also known as Fools Gold is the most common of the sulfide minerals.Pyrite is called Fool's Gold because of it's pale brass yellow color and
glistening metallic luster, but it may be told from gold by it's cubic,
dodecahedral, and octahedral crystals and fine grain masses. Some interesting
facts about pyrite are that it has a greenish black streak, a rating of 6.0 to
6.

5 on the mohs scale, a specific gravity of 5.00 to 5.02 , it creates a weak
electric current when heated and in some of it's various form's it has been used
in early fire arms and fire starting kits. It's biggest commercial use is in
making sulfuric acid but it is also important in nature for forming ore and
mineral deposits.
Science