Iron pyrite, commonly known as Fool's Gold, is a mineral composed of iron and sulfur, with the chemical formula FeS₂. It has a metallic luster and a pale brass-yellow color, which can easily be mistaken for real gold. Found in sedimentary, metamorphic, and igneous rocks, it often forms in cubic crystals. Despite its resemblance to gold, iron pyrite is not valuable and can be brittle, breaking easily. It is often found in coal mines and can produce sulfuric acid when exposed to air and water, leading to environmental concerns.