{{Short description|Arsenic oxide mineral}} {{Infobox mineral | name = Claudetite | category = Oxide minerals | boxwidth = | boxbgcolor = | image = Claudetite-700910.jpg | caption = | formula = As<sub>2</sub> O<sub>3</sub> | IMAsymbol = Ctd<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 = 4.CB.45 | system = Monoclinic | class = Prismatic (2/m) <br/><small>(same H-M symbol)</small> | symmetry = ''P2''<sub>1</sub>/n | unit cell = a = 5.33&nbsp;Å, b = 12.98&nbsp;Å, <br/>c = 4.54&nbsp;Å; β = 94.27°; Z&nbsp;=&nbsp;4 | color = Colorless to white | habit = Thin tabular crystals, fibrous crusts | twinning = Contact or penetration on {100} | cleavage = Perfect on {010} micaceous | fracture = Splintery | tenacity = Flexible | mohs = 2.15 | luster = Vitreous, pearly on cleavage surfaces | refractive = n<sub>α</sub> = 1.870 n<sub>β</sub> = 1.920 n<sub>γ</sub> = 2.010 | opticalprop = Biaxial (−) | birefringence = δ = 0.140 | 2V = 58° (measured) | pleochroism = | streak = | gravity = 4.14–4.15 | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent | other = | references = <ref name= "Handbook">[https://rruff.geo.arizona.edu/doclib/hom/claudetite.pdf Handbook of Mineralogy]</ref><ref name=Webmin>[https://webmineral.com/data/Claudetite.shtml Claudetite data on Webmineral]</ref><ref name=Mindat>[http://www.mindat.org/min-1060.html Claudetite on Mindat]</ref> }} thumb '''Claudetite''' is an arsenic oxide mineral with chemical formula As<sub>2</sub>O<sub>3</sub>. Claudetite is formed as an oxidation product of arsenic sulfides and is colorless or white. It can be associated with arsenolite (the cubic form of As<sub>2</sub>O<sub>3</sub>) as well as realgar (As<sub>4</sub>S<sub>4</sub>), orpiment (As<sub>2</sub>S<sub>3</sub>) and native sulfur.<ref name= "Handbook"/>

It was first described in 1868 for an occurrence in the San Domingo mines, Algarve, Portugal. It was first described by and named for the French chemist Frederick Claudet.<ref name=Webmin/>

== References == {{reflist}}

Category:Arsenic minerals Category:Oxide minerals Category:Monoclinic minerals Category:Minerals in space group 14

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