SULFIDES (SELENIDES, TELLURIDES, ARSENIDES, ANTIMONIDES, BISMUTHIDES)

Sulfides (Sulphides, British English) are compounds that include sulfur. They can be categorized into three types: inorganic sulfides, organic sulfides (often referred to as thioethers), and phosphine sulfides. In the UK, "sulphide" is the preferred spelling. Essentially, a sulfide is formed when sulfur combines with a more electropositive element, and "sulphide" can also refer to thio-ethers.

This important class includes most of the ore minerals. The similar but rarer sulfarsenides are grouped here as well. Sulfide minerals consist of one or more metals combined with sulfur; sulfarsenides contain arsenic replacing some of the sulfur. Sulfides are generally opaque and exhibit distinguishing colours and streaks. (Streak the colour of a mineral’s powder.) The nonopaque varieties (e.g., cinnabar, realgar and oripiment) possess high refractive indices, transmitting light only on the thin edges of a specimen.