Pyrite
Pronunciation : Pyr"ite
Part of Speech : n.;
Etymology : [Cf. F. pyrite. See Pyrites.] (Min.)
Definition : Defn: A common mineral of a pale brass-yellow color and brilliant metallic luster, crystallizing in the isometric system; iron pyrites; iron disulphide. Hence sable coal his massy couch extends, And stars of gold the sparkling pyrite blends. E. Darwin.
pl. Pyrites.
Source : Webster's Unabridged Dictionary, 1913