Sulfide and arsenide minerals

Article By:

Rauchfuss, T. B. School of Chemical Sciences, University of Illinois, Urbana, Illinois.

Waugh, John L. T. Department of Chemistry, University of Hawaii, Honolulu, Hawaii.

Last reviewed:December 2019

DOI:https://doi.org/10.1036/1097-8542.801370

Minerals based on the anions sulfide (S²⁻) and arsenide (As³⁻), or both. The arsenides are structurally similar and have similar properties to the sulfides. Sulfide and arsenide minerals are deposited by hydrothermal solutions. These fluids that are able to dissolve metals such as lead, zinc and copper. Hydrothermal fluids may have originated by exsolution from magma, or they may result from seawater and groundwater that has circulated in a geothermal regime. As these fluids react with minerals, metal sulfides and arsenides will precipitate from solution either in vein deposits or as disseminated crystals in the host rock. Subsequent alteration of the primary sulfide and arsenide minerals by oxidized acidic groundwater will yield a complex variety of sulfate, arsenate and oxide minerals. Percolating groundwater may also dissolve disseminated sulfides in granitic host rocks and reprecipitate new sulfides at the water table boundary by a process known as supergene enrichment. See also: Hydrothermal ore deposits; Hydrothermal vent

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