R. A. Chalmers1, V. C. Farmer2, R. I. Harker3, S. Kelly1 and H. F. W. Taylor1
1 Department of Chemistry, University of Aberdeen, Scotland.
2 The Macaulay Institute for Soil Research, Aberdeen, Scotland.
3 The Johns-Manville Research Center, Manville, New Jersey, U.S.A.; present address, Tem-Press Research Inc., State College, Pennsylvania, U.S.A.

Summary: Reyerite from the original locality in Greenland has been re-examined using chemical analysis, infra-red absorption, X-ray powder and single-crystal diffraction, and thermal weight-loss curves. The unit cell is trigonal with a 9·74, c 19·04 Å, and the space group is probably P3¯. The unit cell contents are probably best represented as KCa14(Si24O60)(OH)5.5H2O, with some minor replacements. The molecular water is lost reversibly below 400° C. There are indications that the crystal structure is based on Si6O18 rings resembling those in beryl, but linked into sheets by additional tetrahedra.

Reyerite closely resembles truscottite, a mineral found originally in Sumatra, but there are distinct differences, especially in the infra-red pattern. It is not yet certain whether or not the two minerals should be considered as distinct species. Synthetic preparations examined resembled truscottite more closely than reyerite.

Mineralogical Magazine; June 1964 v. 33; no. 265; p. 821-840; DOI: 10.1180/minmag.1964.033.265.01
© 1964, The Mineralogical Society
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