clevite

In his letter Prof. Ramsay informed me that the gas had been obtained from the mineral clevite, and that it was quite free from nitrogen and other impurities, which could be removed by circulation over red hot magnesium, oxide of copper, soda lime, and pentoxide of phosphorus.

Scientific American Supplement, No. 1082, September 26, 1896 Various

Professor Ramsay obtained from the rare mineral clevite a volatile gas, the spectrum of which was found to include the yellow prominence-ray.

A Popular History of Astronomy During the Nineteenth Century Fourth Edition 1874