ˈpīˌrīt noun
( -s )
Etymology: Latin pyrites
1. obsolete : pyrites 1
2. : a common mineral that consists of iron disulfide FeS 2 , has a pale brass-yellow color and brilliant metallic luster, crystallizes in isometric forms (as the cube and pyritohedron), and is burned in making sulfur dioxide and sulfuric acid (hardness 6-6.5, specific gravity 4.95-5.10) — called also fool's gold, iron pyrites