Pyrite has been mined for its sulfur content though. During WWII, sulfur was in demand as a strategic chemical and North American native sulfur mines were drying up. A sulfide deposit near Ducktown Tenn. was found to be able to mine pyrite and other sulfides such as pyrrhotite and pentlandite and produce the needed sulfur as well as iron and other metals. The sulfur was used in the production of sulfuric acid, an important chemical for industrial purposes. Now most sulfur production comes from H 2 S gas recovered from natural gas wells.
Color is brassy yellow.
Luster is metallic. Crystals are opaque. Good interpenetration twins called iron crosses are rare. Found commonly in nodules. Also massive, reniform and replaces other minerals and fossils forming pseudomorphs or copies.