Mineralogy of Sulfides and Sulfosalts

Introduction to the Sulfides and Sulfosalts Mineral Class

The sulfides and sulfosalts mineral class has a general formula of A_mX_n, where A represents a metallic element (Fe, Cu, Zn, Pb, As, Sb, Mo, etc.), and X is a sulfide – an anion of sulfur (S^2-). The letters m and n are simply integers. Sometimes, the A (metallic element) position can be shared between several elements, as in chalcopyrite (CuFeS₂).

Sulfides

Sulfides are crucial ore minerals. They are primary ores for cobalt, arsenic, nickel, molybdenum, lead, and copper. These elements have many applications in construction, medicine, chemical, electronics, and other technologies, had important roles in the development of civilization, and played an essential part in the nanotechnology revolution. (Pearce et al., 2006)

There are several hundred known species of sulfide minerals. Pyrite (FeS₂), pyrrhotite (Fe_1−xS (x = 0 to 0.17)), galena (PbS), sphalerite (ZnS), and chalcopyrite (CuFeS₂) are the most common and can be categorized as “rock-forming,” with pyrite and pyrrhotite dominant. (Bowles et al., 2011)

Don’t be afraid pyrrhotite’s strange-looking formula. Certain sulfides exhibit a non-stoichiometric formula.