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X-ray study of psilomelane and cryptomelane

Published online by Cambridge University Press:  14 March 2018

Bibhuti Mukherjee
Bibhuti Mukherjee*
Affiliation:
Geological Survey of India, Calcutta
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Summary

Psilomelane has been shown to be orthorhombic with a 8·254, b 13·40, c 2·864 Å. by the application of Lipson's method. The indexing of powder photographs of psilomelane , where R″ includes the bivalent metals Mn, Ba, Ca, Mg, Co) indicates the space-group P21212 (D22) with one molecule per unit cell. Indexing of powder photographs of psilomelane is not satisfactory with Vaux's axes. Fermor's ‘psilomelane’ is cryptomelane, which is tetragonal with a 9·822, c 2·858 Å. Cryptomelane (KR8O16, where R stands for Mn in different valency states, partly replaced by other cations) is body-centred tetragonal with one molecule per unit cell. Fermor's stalactitic ‘psilomelane’ has an inner dull core of cryptomelane and an outer fine-grained crust of pyrolusite in each needle-shaped body.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 32 , Issue 245 , June 1959 , pp. 166 - 171
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1959

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References

Bernal, (J. D.), Das Gupta, (D. R.), and Mackay, (A. L.), 1957. Nature, vol. 180, p. 645.Google Scholar
Byström, (A.) and Byström, (A. M.), 1950. Acta Cryst., vol. 3, p. 147.[M.A. 11-238].Google Scholar
Fermor, (L. L.), 1909. Mem. Geol. Surv. India, vol. 37, p. 105.Google Scholar
Fleischer, (M.) and Richmond, (W. E.), 1943. Econ. Geol., vol. 38, p. 269.[M.A.94].Google Scholar
Haiaidinger, (W.), 1831. Trans. Roy. Soc. Edinburgh, vol. 2, p. 129.Google Scholar
Hesse, (R.), 1948. Acta Cryst., vol. 1, p. 200.[M.A. 10-527].Google Scholar
Lipson, (H.), 1949. Ibid., vol. 2, p. 43 [M.A. 11 96].Google Scholar
Mathieson, (A. M.) and Wadsley, (A. D.), 1950. Amer. Min., vol. 35, p. 99.[M.A.11-99].Google Scholar
Ramsdell, (L. S.), 1942. Ibid., vol 27, p. 611 [M.A. 8-310].Google Scholar
Richmond, (W. E.) and Fleischer, (M.), 1942. Ibid., p. 607 [M.A. g-310].Google Scholar
Vaux, (G.), 1937. Min. Mag., vol. 24, p. 521.Google Scholar
Wadsley, (A. D.), 1953. Acta Cryst., vol. 6, p. 433.[M.A. 12-93, 12-328].Google Scholar