A mineral form of iron(II) sulphide, FeS2. Superficially it resembles gold in appearance, hence it is also known as fool's gold, but it is harder and more brittle than gold (which may be cut with a knife). Pyrite crystallizes in the cubic system, is brass yellow in colour, has a metallic lustre, and a hardness of 6–6.5 on the Mohs' scale. It is the most common and widespread of the sulphide minerals and is used as a source of sulphur for the production of sulphuric acid. Sources include the Rio Tinto mines in Spain.
Subjects: Earth Sciences and Geography — Chemistry.