Chalcopyrite

a very common mineral, copper iron sulfide, CuFeS 2 , occurring in brass-yellow crystals or masses: the most important ore of copper; copper pyrites.
noun
a widely distributed yellow mineral consisting of a sulphide of copper and iron in tetragonal crystalline form: the principal ore of copper. Formula: CuFeS2 Also called copper pyrites
chalcopyrite
(kāl’kə-pī’rīt’)
A brassy yellow, metallic, tetragonal mineral, usually occurring as shapeless masses of grains. Chalcopyrite is found in igneous rocks and copper-rich shales, and it is an important ore of copper. Because of its shiny look and often yellow color, it is sometimes mistaken for gold, and for this reason it is also called fool’s gold. Chemical formula: CuFeS2.