pyrite

n. common sulfide mineral, iron disulfide, "fool's gold"

The mineral pyrite, or iron pyrite, is iron sulfide, FeS2. It has isometric crystals that usually appear as cubes. The cube faces may be striated (parallel lines on crystal surface or cleavage face) as a result of alternation of the cube and pyritohedron faces. Pyrite also frequently occurs as octahedral crystals and as pyritohedra (a dodecahedron with pentagonal faces). It has a slightly uneven and conchoidal fracture, a hardness of 6–6.5, and a specific gravity of 4.95–5.10. It is brittle, meaning it breaks or powders easily. It can be identified in the field by the sulfur smell of the powdered mineral. Its metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold due to many miners mistaking it for the real thing, though small quantities of actual gold are sometimes found in pyrite. In fact, such pyrite is a valuable ore of gold.
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Noun
1. a common mineral (iron disulfide) that has a pale yellow color
(synonym) iron pyrite, fool's gold
(hypernym) mineral
(substance-meronym) selenium, Se, atomic number 34

n. pyrite, common sulfide mineral, iron disulfide; stone that produces sparks when struck, "fool's gold"

n. pyrite, common sulfide mineral, iron disulfide, "fool's gold"