Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-27T11:37:35.709Z Has data issue: false hasContentIssue false

Relationships among 2:1 layer silicates

Published online by Cambridge University Press:  05 July 2018

E. J. W. Whittaker*
Affiliation:
Department of Geology and Mineralogy, University of Oxford

Summary

The relationships between the 2:1 layer silicates are discussed in terms of the charge balance between the ions occupying X, Y, and Z sites. This brings out the relationship of glauconite to the illites, and clarifies the reason for the ideal occupancy of the Y sites in montmorillonite. It not only shows hectorite, saponite, and sauconite to be tri-octahedral smectites, but also shows vermiculite to be a tri-octahedral analogue of the illites. Apparently anomalous differences in permitted compositions of the di-octahedral and tri-octahedral micas are explained in terms of mismatch between the tetrahedral and octahedral layers, and it is shown that ephesite is to be regarded as a tri-octahedral common mica, not an analogue of margarite. Anandite is the nearest known naturally occurring equivalent to a tri-octahedral analogue of margarite, but the true analogue is a barium magnesium mica synthesized by Frondel and Ito.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1969

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Deer, (W. A.), HowlE, (R. A.), and Zussman, (J.), 1962. Rock-forming Minerals, vol. 3, Sheet silicates. London (Longmans).Google Scholar
Frondel, (C.) and Ito, (J.), 1968. Arkiv Min. Geol. 4, 445.Google Scholar
Lovering, (J. F.) and Widdowson, (J. R.), 1968. Min. Mag. 36, 871.Google Scholar
Pattiaratchx, (D. B.), Saari, (E.), and Sahama, (Th.G.), 1967. Ibid. 36, 1.CrossRefGoogle Scholar
Radoslovitch, (E. W.), 1960. Acta Cryst. 13, 919.CrossRefGoogle Scholar
Schaller, (W. T.), Carron, (M. K.), and Fleischer, (M.), 1967. Amer. Min. 52, 1689.Google Scholar