Jacobsite: Difference between revisions

| formula = iron(II,III) manganese oxide, (Mn,Mg)Fe₂O₄

| IMAsymbol = Jcb<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref>

| symmetry = ''Fd{{overline|3}}m'' (no. 227)

| mohs = 5.5–6.5

| refractive = ~2.3

'''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 (Mn,Mg)Fe₂O₄ or with [[Redox|oxidation states]] and substitutions:

[[File:Jacobsite-d05-134a.jpg|thumb|left|Jacobsite, N'Chwaning Mines, [[Kuruman]], Kalahari manganese fields, [[Northern Cape Province]], South Africa. Size 3.8 x 3.5 x 3.2 cm]]

{{clear left}}

It occurs as a primary phase or as alteration of other manganese minerals during [[metamorphism]] of manganese deposits.<ref name=Webmin/> Typical associated minerals include [[hausmannite]], [[galaxite]], [[braunite]], [[pyrolusite]], [[coronadite]], [[hematite]] and magnetite.<ref name=Handbook/> 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, Sweden|Nordmark]], [[Filipstad]], [[Värmland]], [[Sweden]].<ref name=Mindat/>

[[Category:Iron(II,III) minerals]]

[[Category:Manganese(II,III) minerals]]

[[Category:Magnesium minerals]]

[[Category:Minerals in space group 227]]

[[Category:Minerals described in 1869]]