Pyrite \Pyr"ite\, n.; pl. Pyrites. [Cf. F. pyrite. See Pyrites.]

(Min.) 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.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Pyrites \Py*ri"tes\, n. [L., fr. Gr. ?, fr. ? fire. See Pyre.]

(Min.) A name given to a number of metallic minerals, sulphides of iron, copper, cobalt, nickel, and tin, of a white or yellowish color.

Note: The term was originally applied to the mineral pyrite, or iron pyrites, in allusion to its giving sparks when struck with steel.

Arsenical pyrites, arsenopyrite.

Auriferous pyrites. See under Auriferous.

Capillary pyrites, millerite.

Common pyrites, isometric iron disulphide; pyrite.

Hair pyrites, millerite.

Iron pyrites. See Pyrite.

Magnetic pyrites, pyrrhotite.

Tin pyrites, stannite.

White iron pyrites, orthorhombic iron disulphide; marcasite. This includes cockscomb pyrites (a variety of marcasite, named in allusion to its form), spear pyrites, etc.

Yellow, or Copper, pyrites, the sulphide of copper and iron; chalcopyrite.

Source: Webster's Revised Unabridged Dictionary (1913)