PYRITES

(Yunanca köken — orijinale bakınız.) Sulphurets of copper and iron, commonly distinguished as copper and ironpjrites. The former is the principal ore of copper; the latter is an abundant natural product of a bra yellow colour. When exposed to air and moisture, especially after having been heated, it absorbs oxygen, and yields sulphate of iron, or green vitriol. The term is derived from ^'j^,fire; either because they sometimes spontaneously ignite, or as being hard enough to strike fire with steel. [s. 1015]