Editing Atacamite

{{Short description|Halide evaporite mineral}}
{{Infobox mineral
| name        = Atacamite
| boxwidth    = 
| boxbgcolor  = 
| image       = Atacamite on malachite - Mt Gunson mines, South Australia.jpg
| imagesize   = 260px
| alt         = 
| caption     = Atacamite from Mt. Gunson mines, South Australia
| category    = [[Halide mineral]]
| formula     = Cu<sub>2</sub>Cl(OH)<sub>3</sub>
|IMAsymbol=Ata<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>
| molweight   = 
| strunz      = 3.DA.10a
| dana        = 
| system      = [[Orthorhombic]]
| class       = Dipyramidal (mmm) <br/>[[H-M symbol]]: (2/m 2/m 2/m)
| symmetry    = ''Pnma''
| unit cell   = a = 6.03, b = 9.12 <br/>c = 6.865&nbsp;[Å]; Z&nbsp;=&nbsp;4
| color       = Bright green, dark emerald-green to blackish green
| colour      = 
| habit       = Slender prismatic crystals, fibrous, granular to compact, massive
| twinning    = Contact and penetration with complex twinned groupings
| cleavage    = Perfect on {010}, fair on {101}
| fracture    = Conchoidal
| tenacity    = Brittle
| mohs        = 3–3.5
| luster      = Adamantine to vitreous
| streak      = Apple green
| diaphaneity = Transparent to translucent
| gravity     = 3.745–3.776
| density     = 
| polish      = 
| opticalprop = Biaxial (−)
| refractive  = n<sub>α</sub> = 1.831 n<sub>β</sub> = 1.861 n<sub>γ</sub> = 1.880
| birefringence = δ = 0.049
| pleochroism = X = pale green; Y = yellow-green; Z = grass-green
| 2V          = Calculated: 74°
| dispersion  = r < v, strong
| extinction  = 
| length fast/slow =
| fluorescence = 
| absorption  = 
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| impurities  = 
| alteration  = 
| other       = 
| prop1       = 
| prop1text   = 
| references  = <ref name=Mindat>[http://www.mindat.org/min-406.html Atacamite on Mindat.org]</ref><ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/atacamite.pdf Handbook of Mineralogy]</ref><ref name=Webmin>[http://www.webmineral.com/data/Atacamite.shtml Atacamite on Webmineral]</ref><ref>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Atacamite Mineralienatlas]</ref>
}}

'''Atacamite''' is a [[copper]] [[halide mineral]]: a [[Dicopper chloride trihydroxide|copper(II) chloride hydroxide]] with formula Cu<sub>2</sub>Cl(OH)<sub>3</sub>. It was first described for deposits in the [[Atacama Desert]] of [[Chile]] in 1802 by [[Dmitri Alekseyevich Gallitzin|Dmitri de Gallitzin]].<ref name="Mindat" /> The Atacama Desert is also the namesake of the mineral.

== Occurrence ==
Atacamite is [[Polymorphism (materials science)|polymorphous]] with [[botallackite]], [[clinoatacamite]], and [[paratacamite]].<ref name="Mindat" /> Atacamite is a comparatively rare mineral, formed from primary copper minerals in the [[oxidation]] or [[weathering]] zone of arid climates. It has also been reported as a [[volcanic sublimate]] from [[fumarole]] deposits, as sulfide alteration products in [[black smoker]]s.<ref name="HBM" /> The mineral has also been found naturally on oxidized copper deposits in Chile, [[China]], [[Russia]], [[Czech Republic]], [[Arizona]], and [[Australia]].<ref name=":0" /> It occurs in association with [[cuprite]], [[brochantite]], [[linarite]], [[caledonite]], [[malachite]], [[chrysocolla]] and its polymorphs.<ref name="HBM" />

=== Synthetic Occurrence ===
Atacamite has been discovered in the patina of the [[Statue of Liberty]], and as alteration of ancient [[bronze]] and copper [[Artifact (archaeology)|artifacts]]. The bronze of the [[Antikythera mechanism]] had turned to atacamite under the sea.<ref>{{cite journal |last1=Alex Wilkins |title=Ancient computer's gears may not have been able to turn |journal=New Scientist |date=Apr 17, 2025 |url=https://www.newscientist.com/article/2476675-ancient-computers-gears-may-not-have-been-able-to-turn/}}</ref>

The mineral has been found as a pigment in [[sculpture]], [[Manuscript|manuscripts]], [[Map|maps]], and [[Fresco|frescoes]] discovered in [[Eurasia]], [[Russia]], and [[Persia]].<ref name=":0">{{Cite web|url=http://cameo.mfa.org/wiki/Atacamite|title=Atacamite – CAMEO|website=cameo.mfa.org|language=en|access-date=2017-10-15}}</ref>

=== Biomineral === 
Atacamite occurs as a biomineral in the jaws of [[Glycera (genus)|bloodworms]].<ref name="Lichtenegger">{{cite journal|date=October 2002|title=High abrasion resistance with sparse mineralization: copper biomineral in worm jaws|journal=Science|volume=298|issue=5592|pages=389–92|bibcode=2002Sci...298..389L|doi=10.1126/science.1075433|pmid=12376695|vauthors=Lichtenegger HC, Schöberl T, Bartl MH, Waite H, Stucky GD|s2cid=14001250}}</ref><ref name="Stucky2003">{{cite journal  |vauthors=Lichtenegger HC, Schöberl T, Ruokolainen JT, etal |title=Zinc and mechanical prowess in the jaws of Nereis, a marine worm |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=100 |issue=16 |pages=9144–9 |date=August 2003 |pmid=12886017 |pmc=170886 |doi=10.1073/pnas.1632658100 |bibcode=2003PNAS..100.9144L |doi-access=free }}</ref>

<gallery>
Atacamite-235102.jpg|Atacamite prisms from Chile
Harvard Museum of Natural History. Atacamite. Miraflores Mine, Tierra Amarilla, Atacama, Chile (DerHexer) 2012-07-20.jpg|Atacamite from Chile displayed in the [[Harvard Museum of Natural History]]
Atacamite-168148.jpg|Atacamite from Mt. Gunson, South Australia
</gallery>

{{clear}}

==References==
{{commons category|Atacamite}}
{{reflist}}

==External links==
*[https://web.archive.org/web/20050911055400/http://mineral.galleries.com/minerals/halides/atacamit/atacamit.htm Mineral galleries]

[[Category:Copper(II) minerals]]
[[Category:Chloride minerals]]
[[Category:Hydroxide minerals]]
[[Category:Orthorhombic minerals]]
[[Category:Minerals in space group 62]]
[[Category:Minerals described in 1802]]


{{Halide-mineral-stub}}