PYRITES

(Yunanca köken — orijinale bakınız.) Sulphurets of copper and Iron, commonly distinguished as copper and iron pyrites. The former is the principal ore of copper; the latter is an abundant natural product of a bra -yellow colour. When exposed to nir and moisture, especially after having been heated. It absorbs oxygen, and yields sulphate of iron, or green vitriol. Tbe term is derived from mp, fire; either because they sometimes spontaneously ignite, or as being hard enough to strike fire with steel 3 s [s. 1021]