Margaritasite is a yellow, caesium-bearing mineral in the carnotite group. Its chemical formula is (Cs, K, H3O)2(UO2)2V2O8·H2O and its crystal system is monoclinic (space group P21/a[3]).

Margaritasite
General
CategoryCarnotite group
Formula
(repeating unit)
(Cs, K, H3O)2(UO2)2V2O8·H2O
IMA symbolMgt[1]
Strunz classification7/E.11-60
Dana classification40.2a.28.2
Crystal systemMonoclinic
Crystal class2/m – Prismatic
Space groupP21/a (no. 14)
Unit cella = 10.514(3) Å, b = 8.425(3) Å, c = 7.252(5) Å β = 106.01°
Identification
ColorYellow
Crystal habitTabular crystals, typically massive
DiaphaneityTranslucent
Specific gravity5.41
Optical propertiesBiaxial (−)
α = [< 1.83] (synthetic). β = 2.49(1) γ = > 2.7
2V angle45.5◦
Other characteristics Radioactive
References[2][3][4]

Name and discovery

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It was first described in 1982 from the Margaritas uranium deposit in the Peña Blanca district of the municipality of Aldama, in the Mexican state of Chihuahua.

See also

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References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Mindat.org – Margaritasite
  3. ^ a b Appleman, D.E.; Evans, H.T. (1965). "The crystal structures of synthetic anhydrous carnotite, K2(UO2)2V2O8, and its cesium analogue, Cs2(UO2)2V2O8". American Mineralogist. 50: 825–842. Retrieved 30 December 2020.
  4. ^ "Handbook of Mineralogy – Margaritasite" (PDF). Archived from the original (PDF) on 2012-10-01. Retrieved 2013-01-25.