Minerals: Which mineral is known as fool's gold?

Pyrite earned the nickname "fool's gold" due to its brassy-yellow metallic appearance that can deceive inexperienced prospectors into thinking they've found gold. Pyrite is iron sulfide (FeS₂) and is significantly lighter and harder than real gold. Unlike gold, pyrite produces sparks when struck against steel and has a greenish-black streak when scratched on porcelain. Pyrite is commonly found in sedimentary rocks and hydrothermal veins, and while not as valuable as gold, it has industrial uses in sulfuric acid production.