Arsenic minerals

Realgar ( ), also known as arsenic blende, ruby sulphur or ruby of arsenic, is an arsenic sulfide mineral with the chemical formula . It is a soft mineral occurring in monoclinic crystals, or in granular, compact, or powdery form, often in association with the related mineral, orpiment (). It is orange-red in color, and burns with a bluish flame releasing fumes of arsenic and sulfur. It is trimorphous with pararealgar and bonazziite.

Orpiment, also known as yellow arsenic blende, is a deep-colored, orange-yellow arsenic sulfide mineral with formula . It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and may be formed through sublimation.

Arsenopyrite (IMA symbol: Apy) is an iron arsenic sulfide (FeAsS). It is a hard (Mohs 5.5–6) metallic, opaque, steel grey to silver white mineral with a relatively high relative density of 6.1.

Cobaltite is an arsenide and sulfide mineral with the mineral formula CoAsS. It is the naming mineral of the cobaltite group of minerals, whose members structurally resemble pyrite (FeS2).

Proustite is a sulfosalt mineral consisting of silver sulfarsenide, Ag3AsS3, known also as ruby blende, light red silver, arsenic-silver blende or ruby silver ore, and an important source of the metal. It is closely allied to the corresponding sulfantimonide, pyrargyrite, from which it was distinguished by the chemical analyses of Joseph L. Proust (1754–1826) in 1804, after whom the mineral received its name.

Arsenolite is an arsenic mineral, with chemical formula As2O3. It is formed as an oxidation product of arsenic sulfides. Commonly found as small octahedra, it is white, but impurities of realgar or orpiment may give it a pink or yellow hue. It can be associated with its dimorph claudetite (a monoclinic form of As2O3) as well as realgar (As4S4), orpiment (As2S3) and erythrite, Co3(AsO4)2·8H2O.

Gersdorffite or Nickel glance (trivial name) is a nickel arsenic sulfide mineral with formula NiAsS. It crystallizes in the isometric system showing diploidal symmetry. It occurs as euhedral to massive opaque, metallic grey-black to silver white forms. Gersdorffite belongs to a solid solution series with cobaltite, CoAsS. Antimony freely substitutes also leading to ullmannite, NiSbS. It has a Mohs hardness of 5.5 and a specific gravity of 5.9 to 6.33.

Polybasite is a sulfosalt mineral of silver, copper, antimony and arsenic. Its chemical formula is .

Hutchinsonite is a sulfosalt mineral of thallium, arsenic and lead with formula . Hutchinsonite is a rare hydrothermal mineral.

Jordanite is a sulfosalt mineral with chemical formula in the monoclinic crystal system, named after the German scientist H. Jordan (1808–1887) who discovered it in 1864.

Stibarsen or allemontite is a natural form of arsenic antimonide (AsSb) or antimony arsenide (SbAs). The name stibarsen is derived from Latin stibium (antimony) and arsenic, whereas allemontite refers to the locality Allemont in France where the mineral was discovered. It is found in veins at Allemont, Isère, France; Valtellina, Italy; and the Comstock Lode, United States; and in a lithium pegmatites at Varuträsk, Sweden. Stibarsen is often mixed with pure arsenic or antimony, and the original description in 1941 proposed to use stibarsen for AsSb and allemontite for the mixtures. Since 1982,

Lorándite is a thallium arsenic sulfosalt with the chemical formula: TlAsS2. Though rare, it is the most common thallium-bearing mineral. Lorándite occurs in low-temperature hydrothermal associations and in gold and mercury ore deposits. Associated minerals include stibnite, realgar, orpiment, cinnabar, vrbaite, greigite, marcasite, pyrite, tetrahedrite, antimonian sphalerite, arsenic and barite.

Geocronite is a mineral, a mixed sulfosalt containing lead, antimony, and arsenic with a formula of Pb14(Sb, As)6S23. Geocronite is the antimony-rich endmember of a solid solution series. The arsenic-rich endmember is named jordanite. It occurs as grey, black, to silvery white monoclinic crystals. It is found in hydrothermal veins usually associated with other similar minerals, particularly the sulfides of iron and copper.

Glaucodot is a cobalt iron arsenic sulfide mineral with formula . The cobalt:iron(II) ratio is typically 3:1 with minor nickel substituting. It forms a series with arsenopyrite . It is an opaque grey to tin-white typically found as massive forms without external crystal form. It crystallizes in the orthorhombic system. The locality at Håkansboda, Sweden has rare twinned dipyramidal crystals (see photo). It is brittle with a Mohs hardness of 5 and a specific gravity of 5.95. It occurs in high temperature hydrothermal deposits with pyrrhotite and chalcopyrite. Glaucodot is classed as a sulfide i

Alacránite (As8S9) is an arsenic sulfide mineral first discovered in the Uzon caldera, Kamchatka, Russia. It was named for its occurrence in the Alacrán silver/arsenic/antimony mine. Pampa Larga, Chile. It is generally more rare than realgar and orpiment. Its origin is hydrothermal. It occurs as subhedral to euhedral tabular orange to pale gray crystals that are transparent to translucent. It has a yellow-orange streak with a hardness of 1.5. It crystallizes in the monoclinic crystal system. It occurs with realgar and uzonite as flattened and prismatic grains up to 0.5 mm across.

thumb Claudetite is an arsenic oxide mineral with chemical formula As2O3. Claudetite is formed as an oxidation product of arsenic sulfides and is colorless or white. It can be associated with arsenolite (the cubic form of As2O3) as well as realgar (As4S4), orpiment (As2S3) and native sulfur.

Freibergite is a complex sulfosalt mineral of silver, copper, iron, antimony and arsenic with formula . It has cubic crystals and is formed in hydrothermal deposits. It forms one solid solution series with tetrahedrite and another with argentotennantite. Freibergite is an opaque, metallic steel grey to black and leaves a reddish-black streak. It has a Mohs hardness of 3.5 to 4.0 and a specific gravity of 4.85 to 5. It is typically massive to granular in habit with no cleavage and an irregular fracture.

Zykaite or zýkaite is a grey-white mineral consisting of arsenic, hydrogen, iron, sulfur and oxygen with formula: Fe3+4(AsO4)3(SO4)(OH)·15(H2O). This dull mineral is very soft with a Mohs hardness of only 2 and a specific gravity of 2.5. It is translucent and crystallizes in the orthorhombic crystal system.

Aktashite is a rare arsenic sulfosalt mineral with formula Cu6Hg3As4S12. It is a copper mercury-bearing sulfosalt and is the only sulfosalt mineral with essential Cu and Hg yet known. It is of hydrothermal origin. It was published without approval of the IMA-CNMNC, but recognized as valid species by the IMA-CNMNC Sulfosalts Subcommittee (2008).

Seligmanite is a rare mineral, with the chemical formula PbCuAsS3. Originally described from the Lengenbach Quarry, Valais Canton, Switzerland; it has also been found in the Raura district, Lima Region, Peru; at Tsumeb, Oshikoto Region, Namibia; and at the Sterling Mine, Sussex County, New Jersey, US.

Sartorite is a lead arsenic sulfide with the chemical formula PbAs2S4 and as type locality the Lengenbach Quarry in Legenbach, Binnental, Valais, Switzerland. Historically, sartorite has been thought isomorphic to chalcostibite, emplectite, and zinckenite, but was definitively distinguished from the others in 1939.

Pääkkönenite is a metallic grey mineral with the molecular formula Sb2AsS2. It is named after Veikko Pääkkönen (1907–1980), a Finnish geologist.

Baumhauerite (Pb3As4S9) is a rare lead sulfosalt mineral. It crystallizes in the triclinic system, is gray-black to blue-gray and its lustre is metallic to dull. Baumhauerite has a hardness of 3.

Gratonite is a lead-arsenic sulfosalt mineral, with the chemical composition Pb9As4S15. It is considered a low-temperature dimorph of jordanite. Gratonite was discovered in 1939 at the Excelsior Mine, Cerro de Pasco, Peru. It is named in honor of geologist L. C. Graton (1880–1970), who had a long-standing association with the Cerro de Pasco mines. The other location where it is found is the Rio Tinto mine, Minas de Riotinto (Huelva), Spain. The crystals are very similar to those from Cerro de Pasco.

Wakabayashilite is a rare arsenic, antimony sulfide mineral with formula .

Christite is a mineral with the chemical formula TlHgAsS3. It is named after Dr. Charles L. Christ, a member of the U.S. Geological Survey. It usually comes in a crimson red or bright orange color. It has a density of 6.2 and has a rating between 1 and 2 on Mohs Hardness Scale. Christite has an adamantine luster and leaves behind an orange streak. Its crystal system is monoclinic with possible crystal classes of twofold symmetry, mirror plane symmetry, and twofold with a mirror plane. This means it can have radial symmetry, mirror plane symmetry, or mirror plane symmetry perpendicular to the t

Galkhaite is a rare and chemically complex sulfosalt mineral from a group of natural thioarsenites. Its formula is , making the mineral the only known natural Cs-Hg and Cs-As phase. It occurs in Carlin-type hydrothermal deposits.

Pearceite is one of the four so-called "ruby silvers", pearceite , pyrargyrite , proustite and miargyrite . It was discovered in 1896 and named after Dr Richard Pearce (1837–1927), a Cornish–American chemist and metallurgist from Denver, Colorado.

Biehlite is an exceptionally rare mineral, an antimony arsenic bearing molybdate with formula . It comes from Tsumeb.

Tilasite is an arsenate mineral gemstone, with the elemental formula CaMg(AsO4)F. It prefers the monoclinic form of crystal, and has Mohs hardness of 5. It was named in 1895 by Hjalmar Sjögren in honor of Daniel Tilas, who was once director of mines for Sweden, and a regional governor for Västmanland. It was first discovered in Langban, Varmland.

Lautite is a rare mineral belonging to the class of sulfides and sulfosalts with the general formula CuAsS. It is orthorhombic and is known to form up to 2.3 cm long prismatic or flat crystals. It is also found as grains or masses.

Routhierite is a rare thallium sulfosalt mineral with formula .

Zimbabweite is a yellow brown mineral with orthorhombic crystal habit and a hardness of 5, with formula . It is generally classed as an arsenite but is notable for also containing niobium and tantalum. It was discovered in 1986 in kaolinized pegmatite, i.e. weathered to clay, in Zimbabwe.

Pararealgar is an arsenic sulfide mineral with the chemical formula , also represented as AsS. It forms gradually from realgar under exposure to light. Its name derives from the fact that its elemental composition is identical to realgar, . It is soft with a Mohs hardness of 1 - 1.5, is yellow orange in colour, and its monoclinic prismatic crystals are very brittle, easily crumbling to powder.

Argentobaumhauerite (IMA symbol: Abha) is a rare mineral with the chemical formula AgPbAsS. Its type locality is the Binn valley in Switzerland.

thumb|Red Getchellite and yellow Orpiment from the [[Getchell Mine, the type locality.]]

Enneasartorite is a very rare mineral with formula Tl6Pb32As70S140. It belongs to sartorite homologous series. It is related to other recently approved minerals of the sartorite series: hendekasartorite and heptasartorite. All come from Lengenbach quarry in Switzerland, which is famous for thallium sulfosalts. Enneasartorite is chemically similar to edenharterite and hutchinsonite.

Madocite is a mineral with a chemical formula of . Madocite was named for the locality of discovery, Madoc, Ontario, Canada. It is found in the marbles of the Precambrian Grenville Limestone. It is orthorhombic (rectangular prism with a rectangular base) and in the point group mm2. Its crystals are elongated and striated along [001] to a size of 1.5 mm.

Reinerite is a rare arsenite (arsenate(III)) mineral with chemical formula Zn3(AsO3)2. It crystallizes in the orthorhombic crystal system.

thumb | right | One white crystal group of the very rare arsenate-borate mineral teruggite from the TL in Loma Blanca, Argentina and only one of three known localities worldwide. Teruggite is a mineral with the chemical formula Ca4MgAs2B12O22(OH)12·12H2O. It is colorless. Its crystals are monoclinic prismatic. It is transparent. It is not radioactive. It has vitreous luster. Teruggite is rated 2.5 on the Mohs Scale of hardness.

Fettelite, also known as sanguinite, is a mercury-sulfosalt mineral with the chemical formula Ag16HgAs4S15. The mineral was first described by Wang and Paniagua (1996) who named it after M. Fettel, a German field geologist who collected the first samples from Odenwald. It was first collected in the Nieder-Beerbach mine, 10 km south of Darmstadt, Odenwald, Germany. Its normal occurrence is in hydrothermal veins, which can cut gabbro-diorite intrusives. It is closely related to other rare minerals like dervillite, daomanite, vaughanite and criddleite which are also found in the same type lo

Marrite (mar'-ite) is a mineral with the chemical formula PbAgAsS3. It is the arsenic equivalent of freieslebenite (PbAgSbS3), but also displays close polyhedral characteristics with sicherite and diaphorite. Marrite was first described in 1905, and was named in honor of geologist John Edward Marr (1857–1933) of Cambridge, England.

Hendekasartorite is a very rare thallium sulfosalt mineral with formula Tl2Pb48As82S172. It is one of recently approved new members of sartorite homologous series, by enneasartorite and heptasartorite. All new members come from Lengenbach quarry in Switzerland, prolific in terms of thallium sulfosalt minerals. Hendekasartorite is chemically similar to edenharterite and hutchinsonite.

phosphate class mineral, auxiliary "subclass"

Dimorphite, chemical name arsenic sesquisulfide (As4S3), is a very rare orange-yellow arsenic sulfide mineral. In nature, dimorphite forms primarily by deposition in volcanic fumaroles at temperatures of . Dimorphite was first discovered in such a fumarole near Naples, Italy in 1849 by the mineralogist Arcangelo Scacchi (1810–1893). Since its discovery, dimorphite has been found in the Alacrán silver mine near Copiapó, Chile. It has also been reported from Cerro de Pasco, Peru, and the Lavrion District Mines in Attica, Greece.

Fangite is a sulfosalt first discovered in the Mercur gold deposit located in Tooele County Utah. The specimen was found in a boulder in the southern Oquirrh Mountains. The only available specimens of fangite are located in the National Museum of Natural History, Smithsonian Institution. The International Mineralogical Association Commission approved the name Fangite after Dr. Jen-Ho Fang, a crystal chemist affiliated with the University of Alabama, in honor of his significant contributions to crystallography, crystal chemistry, and geostatistics.

Lucabindiite is a mineral discovered in 1998 from the La Fossa crater at Vulcano, the Aeolian islands off the coast of Italy. It has the chemical formula ( and is hexagonal. After months of collecting sublimates and encrustations, the researchers discovered lucabindiite which was found on the surface of pyroclastic breccia. The mineral is named after Luca Bindi, who was a professor of mineralogy and former head of the Division of Mineralogy of the Natural History Museum of the University of Florence.

Gabrielite is an extremely rare thallium sulfosalt mineral with a chemical formula of or .

Achyrophanite ((K,Na)3(Fe3+,Ti,Al,Mg)5O2(AsO4)5) is a yellow mineral, discovered in 2018 and described in 2025.

Jolliffeite is a rare selenide mineral with formula NiAsSe or . It is the selenium analogue of the sulfide mineral gersdorffite, NiAsS, with a common impurity of cobalt, CoAsSe. It is named for its discoverer, Alfred Jolliffe, (1907–1988), a Canadian geologist of Queen's University, Kingston, Ontario.

Tsugaruite is a sulfosalt mineral with the chemical formula . It was first discovered in 1997 in a thin baryte veinlet at the Yunosawa mine in Ikarigaseki, Aomori. In 1998, the International Mineralogical Association approved it as a new mineral species. The mineral was named for its type locality's location in Japan's Tsugaru Peninsula.

Cervandonite is a rare arsenosilicate mineral. It has a chemical formula or . It has a monoclinic crustal structure with supercell (Z=6), the crystal structure was established as a trigonal subcell, with space group R3m and a = 6.508(1)Ǻ, c = 18.520(3) Ǻ, V 679.4(2) Ǻ3, and Z=3. It was first described by Buhler Armbruster in 1988, but it has proven to be problem due to the extreme scarcity of single crystals and its unusual replacement of silicon and arsenic. Cervandonite is named after the location where it was first described, Pizzo Cervandone (Scherbadung), Italy in the Central Alps.

Daliranite is a sulfosalt found in northwestern Iran with a general chemical formula of PbHgAs2S5. The mineral presents a vibrant orange-red color and fibrous habit which makes it resemble the oxide being confused by its similarities in early studies. Named after Dr. Farahnaz Daliran, who has important contributions to research on ore deposits in Iran, this mineral was accepted by the International Mineralogical Association (IMA) in 2007.

Heptasartorite is a very rare mineral with formula Tl7Pb22As55S108. It belongs to sartorite homologous series. It is related to other recently approved minerals of the series: enneasartorite and hendekasartorite. All three minerals come from a quarry in Lengenbach, Switzerland, which is famous of thallium minerals. Chemically similar minerals include edenharterite and hutchinsonite.