Some Crystallographic Studies in the System CaSO4-CaSO4.2H2O I. The Polymorphism of Anhydrous CaSO4

P. Gay
Department of Mineralogy and Petrology, University of Cambridge

Summary: The existence and relationships of the polymorphs of CaSO4 have been studied by X-ray methods. Only two distinct phases are found: no crystallographic evidence is available to support the suggestion that the γ-CaSO4 structure can have two forms, and it is shown that most previous data on the existence of the high temperature α-CaSO4 polymorphs are likely to be due to decomposition of the sulphate.

Some observations on the γ to β-CaSO4 transformation are reported. The structural implications of these results and their relevance to the nature of the transformation are discussed.

Mineralogical Magazine; June 1965 v. 35; no. 270; p. 347-353; DOI: 10.1180/minmag.1965.035.270.08
© 1965, The Mineralogical Society
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