Pyrite

Pyrite is known as “fool’s gold” because of its brassy yellow metallic luster. It is the most abundant sulfide mineral on Earth. Pyrite’s chemical formula is FeS₂, or iron sulfide. It often forms solid cubes, octahedrons, or pyritohedrons. You can find pyrite in many types of rock, including quartz veins, sedimentary layers, and metamorphic rocks.