Cleveite

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Cleveite is an impure radioactive variety of uraninite containing uranium, found in Norway. It has the composition UO₂ with about 10% of the uranium substituted by rare-earth elements.<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

• List of minerals
• List of minerals named after people

References

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