Linnaeite

{{Short description|Cobalt sulfide mineral}}

{{Infobox mineral

| name = Linnaeite

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| image = Linnaeite - USGS Mineral Specimens 722.jpg

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| caption = Linnaeite samples and polished section

| category = Sulfide mineral
Thiospinel group
Spinel structural group

| formula = Co⁺²Co⁺³₂S₄

| IMAsymbol = Lin{{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}}

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| strunz = 2.DA.05

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| system = Cubic

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

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

| unit cell = a = 9.43 Å; Z = 8

| color = Steel gray to gray violet

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| habit = As octahedral crystals; massive, granular

| twinning = On {111}

| cleavage = Imperfect on {001}

| fracture = Subconchoidal

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| mohs = 4.5–5.5

| luster = Metallic

| streak = Grayish-black

| diaphaneity = Opaque

| gravity = 4.8–5.8

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| alteration = Tarnishes in air

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| references = [http://www.mindat.org/min-2409.html Linnaeite on Mindat][http://www.webmineral.com/data/Linnaeite.shtml Linnaeite data on Webmineral][http://rruff.geo.arizona.edu/doclib/hom/linnaeite.pdf Linnaeite on the Handbook of Mineralogy]

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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).

Linnaeite forms a series with polydymite, Ni⁺²Ni⁺³₂S₄.[http://www.mindat.org/min-8710.html Linnaeite-Polydymite Series] Linnaeite is found in hydrothermal veins with other cobalt and nickel sulfides in many localities around the world.