Sulfur mineral may refer to any of the following types of minerals that contain sulfur atoms:
Sulfur is one of the most important elements on Earth, occurring both as a native element and in sulfate and sulfide minerals. Native sulfur is commonly associated with volcanic exhalations, hydrothermal deposits, salt domes and bacterial reduction. Sulfate minerals include gypsum, anhydrite, barite and celestine, and sulfide minerals include pyrite, chalcopyrite, galena, sphalerite and stibnite.
Native sulfur is naturally occurring elemental sulfur, commonly yellow, orange-yellow or brown. It crystallises in the orthorhombic system, has a Mohs hardness of 2 to 2.5, a specific gravity near 2.07 and a resinous lustre, and is a good electrical insulator. It can form by reaction of sulfur dioxide with hydrogen sulfide in volcanic gases, by sulfate-reducing bacteria in anoxic environments, or by precipitation from sulfur-bearing hydrothermal fluids.
Native sulfur deposits occur in volcanic regions, salt-dome caps and evaporite basins. Sicily, Mexico, Japan and Indonesia have historic native sulfur localities. Native sulfur is used mainly to make sulfuric acid, pesticides, gunpowder, rubber vulcanisation and medicines, and is a basic feedstock for the chemical industry.
Sulfate minerals contain the SO₄²⁻ tetrahedron, commonly combined with calcium, magnesium, barium, strontium or lead. Common minerals include gypsum (CaSO₄·2H₂O), anhydrite (CaSO₄), barite (BaSO₄), celestine (SrSO₄), mirabilite (Na₂SO₄·10H₂O) and alunite. Gypsum and anhydrite are major evaporite minerals used in construction, cement retardation and soil amendment, barite is used in drilling muds and radiation shielding, and celestine is the main source of strontium.
Sulfide minerals contain S²⁻ or S₂²⁻, commonly combined with iron, copper, lead, zinc, nickel or cobalt. Common minerals include pyrite (FeS₂), chalcopyrite (CuFeS₂), galena (PbS), sphalerite (ZnS), chalcocite (Cu₂S), stibnite (Sb₂S₃) and molybdenite (MoS₂). Sulfides are the main ore minerals of many metal deposits and are also a source of acid mine drainage and environmental heavy-metal contamination.
Sulfides are unstable in oxidising environments and readily oxidise to sulfate, releasing metals and acid. Pyrite oxidation is the most common reaction in acid mine drainage and a major issue in mine-environment management. Understanding the occurrence and oxidation behaviour of sulfur minerals is important for both resource use and environmental protection.
In mineral classification, native sulfur belongs to the native elements, while sulfates and sulfides form separate chemical classes. The Dana and Strunz systems place sulfides near related sulfosalts, tellurides and arsenides, although boundaries and groupings differ in detail.
Sulfur minerals are economically important. Sulfuric acid is one of the largest-volume industrial chemicals, produced mainly from native sulfur, sulfide smelter by-products and oil and gas desulfurisation. Sulfur is also important in rubber, fertilizers, pesticides, dyes and pharmaceuticals. Sulfur minerals participate in the global sulfur cycle and affect atmospheric chemistry, acid deposition and ocean productivity.