Cobalt minerals

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).

rock concretion on the sea bottom made of layers of iron/manganese hydroxides

thumb|Erythrite (cobalt flower) - Bou Azzer, Atlas Mountains, Morocco. Erythrite, also known as red cobalt, previously cobalt ochre is a secondary hydrated cobalt arsenate mineral with the formula . Erythrite and annabergite, chemical formula , or nickel arsenate form a complete series with the general formula . thumb|left|Erythrite crystals

Skutterudite is a cobalt arsenide mineral containing variable amounts of nickel and iron substituting for cobalt with the ideal formula CoAs3. Some references give the arsenic a variable formula subscript of 2–3. High nickel varieties are referred to as nickel-skutterudite, previously chloanthite. It is a hydrothermal ore mineral found in moderate to high temperature veins with other Ni-Co minerals. Associated minerals are arsenopyrite, native silver, erythrite, annabergite, nickeline, cobaltite, silver sulfosalts, native bismuth, calcite, siderite, barite and quartz. It is mined as an ore of

Spherocobaltite or sphaerocobaltite is the mineral form of Cobalt(II) carbonate (). It is a cobalt bearing member of the calcite group of carbonate minerals, crystallizing in the trigonal crystal system. Rare specimens of pure spherocobaltite typically show a rose-red color, but the color range of impure specimens extends to shades of pink and pale brown.

Roselite is a rare arsenate mineral with chemical formula: . It was first described in 1825 for an occurrence in the Rappold mines of Schneeberg, Saxony, Germany and named by Armand Lévy after German mineralogist Gustav Rose. It occurs in cobalt-bearing hydrothermal environments and was associated with veins of quartz and chalcedony in the type locality. It has also been reported from Italy, Morocco, Chile, British Columbia and several locations in Germany.

Safflorite is a rare cobalt iron arsenide mineral with the chemical formula . Pure safflorite is , but iron is virtually always present. Safflorite is a member of the three-way substitution series of arsenides known as the loellingite group. More than fifty percent iron makes the mineral loellingite whereas more than fifty percent nickel and the mineral is rammelsbergite. A parallel series of antimonide minerals exist.

Ahlfeldite () is a mineral of secondary origin. It is named after Friedrich Ahlfeld (1892–1982), a German-Bolivian mining engineer and geologist. Its type locality is Virgen de Surumi mine, Pakajake Canyon, Chayanta Province, Potosí Department, Bolivia.

Linnaeite is a cobalt sulfide mineral with the composition Co+2Co+32S4. It was discovered in 1845 in Västmanland, Sweden, and was named to honor Carl Linnaeus (1707–1778).

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

Carrollite, CuCo2S4, is a sulfide of copper and cobalt, often with substantial substitution of nickel for the metal ions, and a member of the linnaeite group. It is named after the type locality in Carroll County, Maryland, US, at the Patapsco mine, Sykesville.

Asbolane, previously cobalt ochre is a manganese (IV) oxy-hydroxide mineral containing also cobalt, nickel, magnesium, and calcium ions. It crystallizes in the hexagonal crystal system. Its chemical formula is .

Bieberite (CoSO4 · 7H2O) is a pinkish red colored sulfate mineral high in cobalt content. The name is derived from the type locality at the copper deposit in Bieber, Hesse, Germany. It has been described and reported as far back as the 1700s. Bieberite primarily occurs as a secondary mineral, forming in cobalt-bearing arsenide and sulfide deposits through oxidation.

Heterogenite is a natural tri-valent cobalt oxyhydroxide mineral. It is the most abundant oxidised cobalt mineral in the Katanga Copperbelt, a region in the Democratic Republic of the Congo. About 70% of known heterogenite is located in the DRC.

thumb|Smaltite - Schneeberg Germany

Cattierite (CoS2) is a cobalt sulfide mineral found in the Democratic Republic of Congo. It was discovered together with the nickel sulfide vaesite by Johannes F. Vaes, a Belgian mineralogist and named after Felicien Cattier, who was chairman of the board of the Union Minière du Haut-Katanga.

Tyrrellite is a selenide mineral that has a chemical formula of . It has been found in the Goldfields District in northern Saskatchewan, as well as in the Petrovice deposit, Czech Republic. It is named after the Canadian geologist Joseph Burr Tyrrell. Joseph Tyrrell was one of the first geologists from the Geological Survey of Canada to do research in the Goldfields District.

Alloclasite, or , is a sulfosalt mineral (IMA symbol: Acl). It is a member of the arsenopyrite group. Alloclasite crystallizes in the monoclinic system and typically forms as columnar to radiating acicular prismatic clusters. It is an opaque steel-gray to silver-white, with a metallic luster and a black streak. It is brittle with perfect cleavage, a Mohs hardness of 5 and a specific gravity of 5.91–5.95.

Penroseite is a rare selenide mineral with formula (Ni,Co,Cu)Se2. It has a gray-steel color and black streak with a hardness of 3. It is an isometric mineral, 2/m. Penroseite was first discovered in 1925 in a Bolivian rhyolite. It was named for Richard Penrose (1863–1931), an economic geologist.

Jamborite is a hexagonal-trigonal, green, mineral consisting of nickel, cobalt, hydroxides and sulphur. Its discovery was first published in 1973.

Aplowite is a very rare mineral with the formula CoSO4•4H2O, a naturally occurring cobalt(II) sulfate tetrahydrate. It is the lower hydrate when compared to bieberite (heptahydrate) and moorhouseite (hexahydrate), and a higher hydrate when compared to cobaltkieserite (monohydrate). It occurs together with moorhouseite within efflorescences.

Fletcherite is a rare thiospinel sulfide mineral with formula . It is an opaque metallic steel gray mineral which crystallizes in the cubic crystal system. It is a member of the linnaeite group.

Trogtalite is a rare selenide mineral with the formula CoSe2. It crystallizes in the cubic system and is part of the pyrite group, consisting of Co2+ and Se22− ions. It has a rose-violet colour and its crystals are opaque. It often occurs as grains. It was thought to be dimorphous with hastite, but this was discredited in 2009. Hastite turned out to be the iron selenide mineral ferroselite. It forms a solid solution series with kruťaite.

Moorhouseite is a rare mineral with the formula CoSO4•6H2O, a naturally occurring cobalt(II) sulfate hexahydrate. It is the lower-hydrate-equivalent of bieberite (heptahydrate) and aplowite (hexahydrate). It is also hydrated equivalent of cobaltkieserite. It occurs together with moorhouseite within efflorescences found in the Magnet Cove Barium Corporation mine in Walton, Nova Scotia, Canada.