View source for Cleveite

{{Short description|Radioactive variety of uraninite}}
[[File:Clevite sample (35321726345).jpg|thumb|The cleveite sample from which Ramsay first purified helium, in the collection of [[University College London]]<ref name="Kirk">{{cite web|last1=Kirk|first1=Wendy L.|title=Cleveite [not Clevite] and helium|url=https://blogs.ucl.ac.uk/museums/2013/01/11/cleveite-and-helium-not-clevite/|website=Museums & Collections Blog|publisher=[[University College London]]|accessdate=18 August 2017}}</ref>]]
'''Cleveite''' is an impure [[radioactivity|radioactive]] variety of [[uraninite]] containing [[uranium]], found in [[Norway]]. It has the composition [[Uranium dioxide|UO<sub>2</sub>]] with about 10% of the uranium substituted by [[rare-earth element]]s.<ref>http://www.mindat.org/min-29957.html Mindat.</ref> It was named after Swedish chemist [[Per Teodor Cleve]].

Cleveite was the first known terrestrial source of [[helium]], which is created over time by [[alpha decay]] of the uranium and accumulates trapped (occluded) within the mineral. The first sample of helium was obtained by [[William Ramsay]] in 1895 when he treated a sample of the mineral with [[acid]].<ref>https://archive.org/details/becquerelraysthe00raylrich Rayleigh, Robert and John Strutt, 1904, The Becquerel rays and the properties of radium, London, E. Arnold.</ref> Cleve and [[Abraham Langlet]] succeeded in isolating helium from cleveite at about the same time.

[[Yttrogummite]] is a variant of cleveite also found in [[Norway]].

==See also==
{{Portal|Earth sciences}}
* [[List of minerals]]
* [[List of minerals named after people]]

==References==
<references/>

[[Category:Uranium(IV) minerals]]
[[Category:Thorium minerals]]
[[Category:Oxide minerals]]


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