Strunz classification 4.BB.05 Space group Fd3m | Crystal system Isometric | |
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Category Oxide mineralsSpinel groupSpinel structural group Crystal class Hexoctahedral (m3m)H-M symbol: (4/m 3 2/m) | ||
Jacobsite is a manganese iron oxide mineral. It is in the spinel group and forms a solid solution series with magnetite. The chemical formula is MnFe2O4 or with oxidation states and substitutions: (Mn2+,Fe2+,Mg)(Fe3+,Mn3+)2O4.
It occurs as a primary phase or as alteration of other manganese minerals during metamorphism of manganese deposits. Typical associated minerals include hausmannite, galaxite, braunite, pyrolusite, coronadite, hematite and magnetite.
It was first described in 1869 and named for the Jakobsberg Mine, Nordmark, Filipstad, Värmland, Sweden.
References
Jacobsite Wikipedia(Text) CC BY-SA