{{Short description|Uranium carbonate mineral}} {{infobox mineral | name = Bayleyite | image = Bayleyite-mrz186a.jpg | alt = | caption = Bayleyite sample from the Ambrosia Lake area, Grants District, New Mexico (size: 4.6 × 2.4 × 1.6 cm) | category = Carbonate mineral | formula = Mg<sub>2</sub>(UO<sub>2</sub>)(CO<sub>3</sub>)<sub>3</sub>·18(H<sub>2</sub>O) |IMAsymbol=Byy<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 = 5.ED.05 | dana = | system = Monoclinic | class = Prismatic (2/m) <br/><small>(same H-M symbol)</small> | symmetry = ''P''2<sub>1</sub>/c | unit cell = a = 26.65 Å, b = 15.31 Å, <br/>c = 6.53 Å; β = 93.07°; Z = 4 | color = Sulfur yellow | colour = | habit = Clusters of prismatic crystals, crusts | twinning = | cleavage = | fracture = Conchoidal | tenacity = | mohs = 2–2.5 | luster = Vitreous | streak = | diaphaneity = Semitransparent | gravity = 2.05 | density = | polish = | opticalprop = Biaxial (−) | refractive = n<sub>α</sub> = 1.453 – 1.455 n<sub>β</sub> = 1.490 – 1.492 n<sub>γ</sub> = 1.498 – 1.502 | birefringence = δ = 0.045 – 0.047 | pleochroism = Visible: X = Pinkish, Y = Light yellow, Z = Light yellow | 2V = Measured: 30° | dispersion = | extinction = | length fast/slow = | fluorescence = Weak; yellow-green to pale greenish under LW and SW | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = 25px Radioactive | prop1 = | prop1text = | references = <ref name=Mindat>[http://www.mindat.org/min-582.html Bayleyite on Mindat.org]</ref><ref name=Webmin>[http://www.webmineral.com/data/Bayleyite.shtml Bayleyite on Webmineral]</ref><ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/bayleyite.pdf Handbook of Mineralogy]</ref> }} '''Bayleyite''' is a uranium carbonate mineral with the chemical formula: Mg<sub>2</sub>(UO<sub>2</sub>)(CO<sub>3</sub>)<sub>3</sub>·18(H<sub>2</sub>O). It is a secondary mineral which contains magnesium, uranium and carbon. It is a bright yellow color. Its crystal habit is acicular but is more commonly found as crusts on uranium bearing ores. It has a Mohs hardness of about 2–2.5.<ref name=Mindat/>
==Occurrence== It was first described in 1948 for an occurrence in the Hillside mine, north of Bagdad, Yavapai County, Arizona and named for mineralogist William Shirley Bayley (1861–1943) of the University of Illinois. It occurs as an efflorescence or coating on other secondary minerals and often is deposited on mine walls and workings. It occurs with schrockingerite, andersonite, swartzite and gypsum in the Hillside mine; with schrockingerite and gypsum in the Hideout mine in Utah; and with tyuyamunite, uranophane, liebigite and carnotite in the Powder River Basin in Wyoming.<ref name=HBM/>
==References== {{reflist}}
Category:Uranium(VI) minerals Category:Carbonate minerals Category:Monoclinic minerals Category:Minerals in space group 14 Category:Minerals described in 1948
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