From Wikipedia, the free encyclopedia
The cleveite sample from which Ramsay first purified helium, in the collection of University College London[1]

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.[2] 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.[3] 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[edit]


  1. ^ Kirk, Wendy L. "Cleveite [not Clevite] and helium". Museums & Collections Blog. University College London. Retrieved 18 August 2017.
  2. ^ Mindat.
  3. ^ Rayleigh, Robert and John Strutt, 1904, The Becquerel rays and the properties of radium, London, E. Arnold.