Jacobsite is a

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy u ...

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...

oxide mineral The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys. The hydroxide-bearing minerals are typically included in the oxide class. The minerals with complex anion groups such as the ...

. It is in the

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals. Properties ...

group and forms a

solid solution A solid solution, a term popularly used for metals, is a homogenous mixture of two different kinds of atoms in solid state and have a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The wor ...

series with

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With ...

. The chemical formula is (Mn,Mg)Fe₂O₄ or with

oxidation states In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. ...

and substitutions: (Mn²⁺,Fe²⁺,Mg)(Fe³⁺,Mn³⁺)₂O₄.Webmineral data
It occurs as a primary phase or as alteration of other manganese minerals during

metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of ...

of manganese deposits. Typical associated minerals include hausmannite, galaxite, braunite,

pyrolusite Pyrolusite is a mineral consisting essentially of manganese dioxide ( Mn O2) and is important as an ore of manganese.. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform c ...

coronadite Coronadite is a black monoclinic mineral containing a ternary oxide of lead and manganese in two oxidation states. The mineral was named after Francisco Vasquez de Coronado Francisco is the Spanish and Portuguese form of the masculine given name ...

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of ...

and magnetite. It is a ferrimagnetic substance, which is weakly attracted by a magnet. It was first described in 1869 and named for the Jakobsberg Mine, Nordmark,

Filipstad Filipstad is a locality and the seat of Filipstad Municipality, Värmland County, Sweden, with 10,644 inhabitants in 2019. Filipstad was granted city privileges in 1611 by Charles IX of Sweden, who named it after his son Duke Carl Philip (1601&n ...

Värmland Värmland () also known as Wermeland, is a ''landskap'' (historical province) in west-central Sweden. It borders Västergötland, Dalsland, Dalarna, Västmanland, and Närke, and is bounded by Norway in the west. Latin name versions are ...

, Sweden. Jacobsite-d05-134a

References

National Pollutant Inventory - Manganese and compounds Fact Sheet
Spinel group Iron(II,III) minerals Manganese(II,III) minerals Magnesium minerals Magnetic minerals Cubic minerals Minerals in space group 227 Minerals described in 1869 {{Manganese minerals