# Curite

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> Source: https://en.wikipedia.org/wiki/Curite
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{{Short description|Rare mineral}}
{{Expand German|date=July 2023}}
{{infobox mineral
| name        = Curite
| category    = [Oxide mineral](/source/Oxide_mineral)
| boxwidth    = 
| boxbgcolor  = 
| image       = Curit - Shinkolobwe.jpg
| imagesize   = 260px
| alt         = 
| caption     = Orange-red curite needles from [Shinkolobwe](/source/Shinkolobwe) mine, [Katanga Province](/source/Katanga_Province), [Democratic Republic of the Congo](/source/Democratic_Republic_of_the_Congo)
| formula     = Pb<sub>3</sub>[(UO<sub>2</sub>)<sub>4</sub>{{Pipe}}O<sub>4</sub>{{Pipe}}(OH)<sub>3</sub>]<sub>2</sub>·2&nbsp;H<sub>2</sub>O<ref name="Lapis" />
| IMAsymbol = Cui<ref name="Warr" />
| molweight   = 
| strunz      = 4.GB.55
| system      = [Orthorhombic](/source/Orthorhombic)
| class       = orthorhombic-dipyramidal; 2/''m''&nbsp;2/''m''&nbsp;2/''m''<ref name="Webmineral" />
| symmetry    = ''Pnam''<ref name="AMCSD" />
| unit cell   = a = 12.551&nbsp;Å, b = 13.02&nbsp;Å, <br/>c = 8.40&nbsp;Å; Z&nbsp;=&nbsp;2
| color       = red, reddish orange, brownish yellow.
| colour      = 
| habit       = needles, acicular, massive, compact earthy.
| twinning    = 
| cleavage    = {100}, imperfect}<ref name="Handbookofmineralogy" />
| fracture    = uneven
| tenacity    = brittle
| mohs        = 4-5
| luster      = adamantine
| streak      = orange
| diaphaneity = transparent
| gravity     = 
| density     = measured: 6.98–7.4; calculated: 7,37<ref name="Handbookofmineralogy" />
| polish      = 
| opticalprop = biaxial (-)
| refractive  = n<sub>α</sub> = 2.060 n<sub>β</sub> = 2.110 n<sub>γ</sub> = 2.150<ref name="Mindat" />
| birefringence = 0.090
| pleochroism = Visible: X = b = pale yellow, Y = a = light red-orange, Z = c = dark red-orange
| 2V          = 70° (measured); 80° (calculated)<ref name="Mindat" />
| dispersion  = 
| extinction  = 
| length fast/slow =
| fluorescence= 
| absorption  =
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| other       = 25px [Radioactive](/source/Radioactive)
| alteration  = 
| references = 
}}

'''Curite''' is a rare [mineral](/source/mineral) with the chemical composition Pb<sub>3</sub>[(UO<sub>2</sub>)<sub>4</sub>{{Pipe}}O<sub>4</sub>{{Pipe}}(OH)<sub>3</sub>]<sub>2</sub>·2&nbsp;H<sub>2</sub>O.<ref name="Lapis" /> It is therefore a hydrated [lead](/source/lead) [uranyl](/source/uranyl) [oxide](/source/oxide), which forms red needles or orange, massive aggregates.

== Etymology and history ==
Curite was first found at [Shinkolobwe](/source/Shinkolobwe) mine (formerly known as "Kasolo mine“) in [Katanga Province](/source/Katanga_Province) in the [Democratic Republic of the Congo](/source/Democratic_Republic_of_the_Congo). [Alfred Schoep](/source/Alfred_Schoep) (1881–1966) described the mineral for the first time in 1921 and named it after physicist and Nobel laureate [Pierre Curie](/source/Pierre_Curie) (1859–1906).<ref name="Schoep" />

== Classification ==
The mineral is classified according to Strunz as part of the uranyl hydroxides, forming its own group with additional cations (K, Ca, Ba, Pb etc.) and primarily UO<sub>2</sub>(O,OH)<sub>5</sub> pentagonal polyhedra with system number 4.GB.55.

Dana classifies the mineral to the oxides and hydroxide, as part of the uranium- and thorium-containing oxides with oxidation state +6 containing Pb, Bi, hydroxyl groups or water.

== Crystal structure ==
[[Image:Schoepite-Curite-Uraninite-214949.jpg|thumb|left|[Paragenesis](/source/Paragenesis) of red curite with yellow  [schoepite](/source/schoepite), pseudomorphic after [wyartite](/source/wyartite) on [uraninite](/source/uraninite) from [Shinkolobwe](/source/Shinkolobwe), [DRC](/source/Democratic_Republic_of_the_Congo)]]
Curite crystallizes orthorhombically in [space group](/source/space_group) Pnama with the lattice parameters ''a''&nbsp;=&nbsp;12.56&nbsp;[Å](/source/Angstrom); ''b''&nbsp;=&nbsp;13.02&nbsp;Å and ''c''&nbsp;=&nbsp;8.40&nbsp;Å<ref name="AMCSD" /> and two formula units per [unit cell](/source/unit_cell).<ref name="Webmineral" />

The crystal structure consists of layers of corner- and edge-sharing uranyl polyhedra, in which the uranyl cation shows both pentagonal-bipyramidal and square-bipyramidal coordination. The lead cations connect these layers by coordinating to the oxygen atoms of uranyl group.<ref name=Burns />

== Radioactivity ==
The mineral is radioactive because of its uranium content of about 63%. Considering the composition with respect to the ideal sum formula, a specific activity of about 113,4&nbsp;k[Bq](/source/Becquerel)/g<ref name="Webmineral" /> can be given. The absolute value of any given mineralogical sample may vary drastically depending on the general composition of the mineral with its matrix, the amount of material and its age.

== Occurrence ==
thumb|Orange microcrystalline curite from Katanga Province, DRC.
Curite is a secondary uranium mineral, which forms by alteration of geologically old [uraninite](/source/uraninite). Additionally, lead atoms form due to radioactive decay.<ref name="Burns" /> Curite is found in the oxidation zone along with [dewindtite](/source/dewindtite), [fourmarierite](/source/fourmarierite), [kasolite](/source/kasolite), [rutherfordine](/source/rutherfordine), [schoepite](/source/schoepite), [soddyite](/source/soddyite), [sklodowskite](/source/sklodowskite), [torbernite](/source/torbernite) and [vandendriesscheite](/source/vandendriesscheite).

Curite has been found, apart from its type locality Shinkolobwe mine, at a further 50 localities, e.g. in [Egypt](/source/Egypt); [Northern Territory](/source/Northern_Territory), Australia; [Baden-Württemberg](/source/Baden-W%C3%BCrttemberg), [Bavaria](/source/Bavaria), [Rhineland-Palatinate](/source/Rhineland-Palatinate) and [Saxony](/source/Saxony), Germany; [Auvergne](/source/Auvergne), [Brittany](/source/Brittany), [Alsace](/source/Alsace) and [Limousin](/source/Limousin), France; [Lombardy](/source/Lombardy) and [Trentino-Alto Adige/Südtirol](/source/Trentino-Alto_Adige%2FS%C3%BCdtirol), Italy; [Northwest Territories](/source/Northwest_Territories), Canada; [Fianarantsoa](/source/Fianarantsoa), Madagascar; [Agder](/source/Agder) and [Telemark](/source/Telemark), Norway; [Karelia](/source/Republic_of_Karelia), Russia; [Namaqualand](/source/Namaqualand), South Africa; [Bohemia](/source/Bohemia) and [Moravia](/source/Moravia), Czechia; [Baranya](/source/Baranya_County) and [Heves](/source/Heves_County), Hungary as well as in [Colorado](/source/Colorado), [New Hampshire](/source/New_Hampshire) and [New Mexico](/source/New_Mexico), USA.<ref name="Fundorte" />

== Precautions ==
Because of its radioactivity, samples of this mineral should be kept in air-tight containers. Inhaling the dust or incorporation should be avoided.

== Literature ==
* {{citation|author=[Paul Ramdohr](/source/Paul_Ramdohr), [Hugo Strunz](/source/Karl_Hugo_Strunz)|date=1978|edition=16.|isbn=3-432-82986-8|pages=560|publisher=Ferdinand Enke Verlag|title=Klockmanns Lehrbuch der Mineralogie}}<!-- auto-translated by Module:CS1 translator -->
* {{citation|author=Petr Korbel, Milan Novák|date=2002|isbn=3-89555-076-0|location=Eggolsheim|pages=111|publisher=Nebel Verlag GmbH|title=Mineralien Enzyklopädie}}<!-- auto-translated by Module:CS1 translator -->

== References ==
<references>
<ref name="AMCSD">
American Mineralogist Crystal Structure Database ([http://rruff.geo.arizona.edu/AMS/result.php?mineral=Curite AMCSD - Curite])
</ref>
<ref name="Burns">
Y. Li, P. C. Burns: ''Investigations of crystal-chemical variability in lead uranyl oxide hydrates. I. CURITE'', In: ''The Canadian Mineralogist'' 2000, ''Band 38'', S. 727–735. ([http://rruff.info/doclib/cm/vol38/CM38_727.pdf PDF 363.2 kB])
</ref>
<ref name="Schoep">
A. Schoep: ''La curite, nouveau minéral radioactif'' In: ''Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences'' 1921, ''173'', 1186–1187. ([https://rruff.info/uploads/CRHSAS173_1186.pdf PDF (French) 91.6 kB])
</ref>
<ref name="Warr">
L. N. Warr: ''IMA–CNMNC approved mineral symbols'' In: ''[Mineralogical Magazine](/source/Mineralogical_Magazine)'' 2021, ''85'' 291–320. DOI= 10.1180/mgm.2021.43 ([https://www.cambridge.org/core/services/aop-cambridge-core/content/view/62311F45ED37831D78603C6E6B25EE0A/S0026461X21000438a.pdf/imacnmnc-approved-mineral-symbols.pdf PDF 320 kB]) 
</ref>
<ref name="Handbookofmineralogy">
''Curite'', In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Hrsg.): ''Handbook of Mineralogy, Mineralogical Society of America'', 2001 ([https://www.handbookofmineralogy.org/pdfs/curite.pdf PDF 69 kB])
</ref>
<ref name="Fundorte">
Localities for curite [http://www.mineralienatlas.de/lexikon/index.php/MineralDataShow?mineralid=865&sections=12 Mineralienatlas] and at [https://www.mindat.org/show.php?id=1197&ld=1#themap Mindat]
</ref>
<ref name="Lapis">
{{citation|author=Stefan Weiß|date=2008|edition=5. vollkommen neu bearbeitete und ergänzte|isbn=978-3-921656-70-9|location=München|publisher=Weise|title=Das große Lapis Mineralienverzeichnis. Alle Mineralien von A – Z und ihre Eigenschaften}}<!-- auto-translated by Module:CS1 translator -->
</ref>
<ref name="Mindat">
Mindat [https://www.mindat.org/min-1197.html Curite]
</ref>
<ref name="Webmineral">
Webmineral [http://webmineral.com/data/Curite.shtml Curite]
</ref>
</references>

== External links ==
{{Commons category|Curite}}
* [Mineralienatlas:Curit](/source/Mineralienatlas%3ACurit) (Wiki)
* [http://www.agab.be/mineralogie/Katanga/curite.html Fotos von Curit auf den Webseiten der Association des Géologues Amateurs de Belgique (AGAB)]

Category:Lead minerals
Category:Oxide minerals
Category:Uranium(VI) minerals
Category:Orthorhombic minerals
Category:Minerals in space group 62

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Adapted from the Wikipedia article [Curite](https://en.wikipedia.org/wiki/Curite) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Curite?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.