Hostname: page-component-84b7d79bbc-5lx2p Total loading time: 0 Render date: 2024-08-04T11:35:29.482Z Has data issue: false hasContentIssue false

A dickite with an elongated crystal habit and its dehydroxylation

Published online by Cambridge University Press:  14 March 2018

E. R. Schmidt
Affiliation:
National Building Research Institute, Pretoria, Union of South Africa
R. O. Heckroodt
Affiliation:
National Building Research Institute, Pretoria, Union of South Africa

Summary

Dickite from a new occurrence at Barkly East, Cape Province, is described and compared with a previously unreported dickite from Postmasburg and a dickite from Ouray, Colorado. The Barkly East dickite crystals are elongated in the direction of the a-axis; the ratio of length to width of crystals varies from 3:1 to 16:1. Optical, electron microscopic, X-ray, and thermal data and a chemical analysis are given. The thermogram of the fraction smaller than 2 µ e.s.d.1 is characterized by a single peak at 600°C., while that of fractions larger than 2 µ e.s.d. shows a double endothermal effect. This two-stage dehydroxylation of dickite on heating is attributed to a particle size effect.

Type
Research Article
Copyright
Copyright © 1959, The Mineralogical Society

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

Davis, (D.W.), Rochow, (T.G.), Rowe, (F.G.), Fuller, (M.L.), Kerr, (P.F.), and Hamilton, (P.K.), 1950. Amer. Petr. Inst., Clay Mineral Standards. Prelim. Rep. No. 6, Columbia University, New York.Google Scholar
Engelhardt, (W. yon), 1955. Zeits. Krist., vol. 106, p. 430.Google Scholar
Frankel, (J.J.), 1949. Mill. Mag., vol. 28, p. 582.Google Scholar
Grim, (R.E.), 1953. Clay Mineralogy (New York: McGraw-Hill).Google Scholar
Hill, (R.D.), 1955. Acta Cryst., vol. 8, p. 120.CrossRefGoogle Scholar
Kerr, (P.F.), Kulp, (S.L.), and Hamilton, (P.K.), 1949. Amer. Pert. Inst., Clay Mineral Standards, Prelim. Rep. No. 3, Columbia University, New York.Google Scholar
Kerr, (P.F.), Hamilton, (P.K.), Pill, (R.J.), Wheeler, (G.V.), Lewis (1). R.), Burkhardt, (W.), Reno, (D.), Taylor, (G.L.), Mielenz, (R.C.), King, (M.E.), and Schieltz, (N.C.), 1950. Ibid., no. 7.Google Scholar
McLaughlin, (R. J. W.), 1955. Clay Min. Bull., vol. 2, no. 14, p. 309.Google Scholar
Mezösi, (J.), 1957. Acta Univ. Szeged. Acta Min.-Petr., vol. 10, p. 67.Google Scholar
Murray, (P.) and White, (J.), 1955. Trans. Brit. Ceram. Soc., vol. 54, p. 137.Google Scholar
Roy, (R.) and Brindley, (G.W.), 1955. Proc. Fourth Nat. Conf. Clays and Clay Minerals (Publ. 456, Nat. Acad. Sci.-Nat. Res. Council, Washington, D.C. 1956).Google Scholar
Roy, (R.) and Osborn, (E.F.), 1954. Amer. Min., vol. 39, p. 853.Google Scholar
Smithson, (F.) and Brown, (G.), 1957. Min. Wag., vol. 31, p. 381.Google Scholar
Whiteside, (H. C. M.), 1941. Trans. Geol. Soc. South Africa, 1942, vol. 44 (for 1941), p. 121.Google Scholar