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Beryllium minerals (euclase and phenakite) from Africa

Published online by Cambridge University Press:  14 March 2018

L. J. Spencer*
Affiliation:
British Museum of Natural History

Extract

With the exception of beryl, there are very few recorded occurrences of beryllium minerals in the whole of Africa. Phenakite is represented by a single small crystal from Tanganyika Territory which was described in this Magazine in 1906. Chrysoberyl has been found in small amount in the Somabula diamond field in Southern Rhodesia, and in Belgian Congo and Gold Coast; and gadolinite a in Gordonia in Cape Province.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1934

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References

page 616 note 1 Spencer, L. J.. Phenacite and other minerals from German East Africa. Min. Mag., 1906, vol. 14, pp. 178-183Google Scholar.

page 616 note 2 Min. Abstr., 2-265, 2-266, 3-266, 5-399

page 616 note 3 Min. Abstr., 4-475.

page 616 note 4 Guyot, M., Description of a crystal of euclase, belonging to my collection, Min. Mag., 1882, vol. 5, p. 107, with crystallographic note by J. H. Collins, p. 108.Google Scholar

page 616 note 5 A much larger crystal from the Urals was described and figured from a plaster cast by N. I. Koksharov (Min. Russlands, 1862, vol. 4, p. ]00). It was 7½ cm. long with a width of 1½ to 2 cm., and was the sixth of the few crystals that have been found in the gold-washings in the region of the Sanarka river

page 616 note 6 Spencer, L. J., Euelase and platinum from diamond-washings in British Guiana. Min. Mag., 1924, vol. 20, pp. 186-192Google Scholar.

page 616 note 1 A. Cavinato, Nuove ricerche sull'euclasio.—Euclasio di valle Aurina, Atti (Rend.) R. Accad. Lincei, C1. Sci. fis. nat. Roma, 1929, set. 6, vol. 10, pp. 656- 664. [Min. Abstr., vol. 4, p. 522.]

page 617 note 1 This locality is about i00 kin. SE. of the phenakite locality in the Kisitwi Mountains described in 1906.

page 618 note 1 Hussak, E., Min. Petr. Mitt. (Tschermak), 1892, vol. 12, p. 474.Google Scholar

page 619 note 1 Dürrfeld, V., Zeits. Kryst. Min., 1910, vol. 47, p. 372 Google Scholar. Diirrfeld had himself made the same error in his first description of euelase crystals from Epprechtstein, Bavaria.

page 619 note 2 This method of giving a table of angles was used for schultenite, Min. Mag., 1926, vol. 21, pp. 151, 153. In the case of euclase c(001) is very rarely developed and no prominent zones pass through its pole ; but as shown in fig. 4 all the prominent zones pass through a(100) and b(010).

page 621 note 1 Letters and indices as in Dana's System of Mineralogy, 6th edit., 1892

page 622 note 1 The largest crystals of phenakite of these two habits in the British Museum collection are : a lenticular crystal 7 cm. wide and 3½ cm. in the direction of the c-axis from S ão Miguel de Piricicaba, Minas Geraes, Brazil ; a prismatic crystal 18 cm. long and 3½ cm. across from Kragerø, Norway.

page 622 note 2 Marked on the sketch-maps given by Gevers, T. W. and Frommurze, H., Trans. Geol. Soc. South Africa, 1930, vol. 32 (for 1929), plates ix and viGoogle Scholar.

page 622 note 3 Gevers, T. W. and Frommurze, H. F., The geology of north-western Damaraland in South-West Africa. Ibid., pp. 31-55.