manganosite

{{Short description|Rare manganese(II) oxide mineral: MnO}}

{{Infobox mineral

| name = Manganosite

| category = Oxide mineral

| boxwidth =

| boxbgcolor =

| image = Zincite-Manganosite-Sonolite-21568.jpg

| imagesize = 260px

| caption = Black manganosite crystals with zincite and sonolite

| formula = Manganese oxide, MnO

| IMAsymbol = Mng{{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}}

| strunz = 4.AB.25

| system = Cubic

| class = Hexoctahedral (m{{overline|3}}m)
H-M symbol: (4/m {{overline|3}} 2/m)

| symmetry = Fm{{overline|3}}m

| unit cell = a = 4.44 Å; Z = 4

| color = Emerald-green, becoming black on exposure to air

| habit = Granular to massive; Octahedral crystals uncommon

| twinning =

| cleavage = Perfect on [100], [010] and [001]

| fracture = Fibrous

| mohs = 5–6

| luster = Vitreous, adamantine to dull

| refractive = n = 2.16–2.17

| opticalprop = Isotropic

| birefringence =

| pleochroism =

| streak = Brown

| gravity = 5.364

| density =

| melt =

| fusibility =

| diagnostic =

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| diaphaneity = Transparent to translucent

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| references = [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Manganosite Mineralienatlas][http://webmineral.com/data/Manganosite.shtml Manganosite data on Webmineral][http://www.mindat.org/min-2503.html Manganosite data from Mindat.org][http://www.handbookofmineralogy.org/pdfs/manganosite.pdf Manganosite in the Handbook of Mineralogy]

}}

Manganosite is a rare mineral composed of manganese(II) oxide MnO. It was first described in 1817 for an occurrence in the Harz Mountains, Saxony-Anhalt, Germany. It has also been reported from Langban and Nordmark, Sweden and at Franklin Furnace, New Jersey. It also occurs in Japan, Kyrgyzstan and Burkina Faso.

It occurs in manganese nodules. It also occurs as alteration of manganese minerals such as rhodocrosite during low oxygen metamorphism and metasomatism.