Color centers, associated rare-earth ions and the origin of coloration in natural fluorites

@article{Bill1978ColorCA,
  title={Color centers, associated rare-earth ions and the origin of coloration in natural fluorites},
  author={Hansson Bill and Georges Calas},
  journal={Physics and Chemistry of Minerals},
  year={1978},
  volume={3},
  pages={117-131}
}
  • H. BillG. Calas
  • Published 1 August 1978
  • Geology
  • Physics and Chemistry of Minerals
Natural colored fluorites were studied by means of optical absorption and electron paramagnetic resonance (EPR). Complex centers involving rare-earth ions and/or oxygen give rise to the various colors observed. These include yttrium-associated F centers (blue), coexisting yttrium and cerium-associated F centers (yellowish-green), the (YO2) center (rose) and the O3−molecule ion (yellow). Divalent rare-earth ions also contribute to the colorations, as for instance Sm3+ (green fluorites), or they… 

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