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Okenite and nekoite (a new mineral) (With Plate I.)

Published online by Cambridge University Press:  14 March 2018

J. A. Gard
Affiliation:
Department of Chemistry, University of Aberdeen
H. F. W. Taylor
Affiliation:
Department of Chemistry, University of Aberdeen

Summary

The unit cell of okenite (CaO.2SiO2.2H2O) has been determined for a specimen from Bombay, India, using a combination of X-ray, electron-microscope, and electron-diffraction methods. It is anorthic with a 9·84, b 7·20, c 21·33Å., α 90·0°, β 103·9°, γ, 111·5°, elongation b, Z 9. These data are compatible with the goniometric results of Boggild (1922) and allow the latter to be interpreted.

A specimen from Crestmore, California, which Eakle (1917) had described as okenite, was also examined. It was found to be a new species, having the same composition as okenite but distinguishable from it by its optical properties, X-ray powder data, and unit cell. The latter is anorthic with a 7·60, b 7·32, c 9·86 Å, α 111° 48′, β 86° 12′, γ 103° 54′, elongation b, Z = 3. Because of the relation to okenite, the name nekoite is suggested.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1956

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References

page 5 note 1 This cell is not in conventional orientation: sec pp. 13 and 16, footnotes.

page 5 note 2 F. von Kobell, Arch. gesammte Naturlehre (Kastner), 1828, vol. 14, p. 333.

page 5 note 3 A. Breithaupt, Ann. Phys. Chem. (Poggendorff), 1845, vol. 64, p. 170.

page 5 note 4 O. B. Boggild, Kgl. Danske Vidensk. Selsk., Math. -fys Medd., 1922, vol. 4, no. 8 [M.A. 2 59].

page 5 note 5 C. E. Tilley and A. R.. Alderman, Min. Mag., ]934, vol. 23, p. 513.

page 5 note 6 H. F. W. Taylor, Proc. Int. Syrup. Reactivity of Solids, Gothenburg, 1952 p. 677.

page 7 note 1 W. A. K. Christie, Rec. Geol. Survey India, 1925, vol. 56, p. 199 [M.A. 3-287].

page 9 note 1 C. E. Challiee, Prec. Physical See., ser. B, 1950, vol. 63, p. 59; J. F. Brown and D. Clark, Aeta Cryst., 1952, vol. 5, p. 615; T. B. Rymer, Brit. Journ. Appl. Phys., 1953, vol. 4, p. 297.

page 10 note 1 R. E. Williams and R. W. G. Wyekoff, Journ. Appl. Phys., 1944, vol. 15, p. 712.

page 13 note 1 This cell, having c > a, is not in the conventional orientation. Application of the transformation matrix 1001/01¯0/100 gives: a 21.33, b 7.20, c 18.30 Å., β 105° fibres parallel to b, cleavage (100).

page 13 note 2 This cell is not in the conventional orientation. Application of the transformation matrix 100/001¯/010 gives: a 9.84, b 21.33, c 7-20 Å.., α 90.0° β 111.5° V 86.1°; fibres parallel to c, cleavage (010).

page 13 note 3 J. F. Brown and D. Clark, loc. cit.

page 13 note 4 L. Heller, Proc. Third Internat. Symposium Chemistry of Cement, London, 1952; Cement and Concrete Association, London, 1954, p. 237.

page 15 note 1 A. S. Eakle, Bull. Dept. Geol, Univ. California, 1917, vol. 10, no. 19, p. 327 [M.A. 1-20].

page 15 note 2 Private communication from W. F. Foshag, 20 July, 1952.

page 15 note 1 This cell is not in the conventional orientation. Application of the transformation matrix 1¯00/001¯/0101¯ gives: a 7.60, b 9.86, c 7.32 Å., α 111° 48‘, β 103°.54, γ, 86° 12’; fibres parallel to c, cleavage (100).

page 18 note 1 In A. S. Eakle, loc. cit.

page 19 note 1 B. E. Warren and J. Biscoe, Zeits. Krist., 1931, vol. 80 p. 391 [M.A. 5-186].

page 20 note 1 H. F. W. Taylor, Acta Cryst., 1955, vol. 8, p. 440.