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Euclase and platinum from diamond-washings in British Guiana

Published online by Cambridge University Press:  14 March 2018

L. J. Spencer*
Affiliation:
Mineral Department of the British Museum (Natural History)

Extract

The euclase here described is not only from a new locality, but it represents an entirely new type of habit for this rare mineral, which is occasionally used as a gem-stone. The crystal aggregates present a strange resemblance to fossils, and fossils not having been found in British Guiana they were submitted to the Geology Department of the British Museum by Mr. R. P. Stewart of Georgetown, Demerara. They had been found by Mr. J. C. Menzies whilst engaged in washing for gold and diamonds in the neighbourhcod of the Kaieteur gorge on the Potaro river, a left tributary of the Essequibo. Both of these gentlemen have interested themselves in the matter and have kindly sent further material for examination.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1924

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References

Page 186 note 1 J. B. Harrison, The geology of the goldfields of British Guiana. London, 1908. Official Map of British Guiana (scale 1 inch to 10 miles), 1913

Page 188 note 1 Meaning French-bean or black French-bean ; plural, ‘foijões pretos’. The brown and pale-coloured Brazilian ‘favas’ (beans) are perhaps represented in the sample of concentrate from British Guiana by one or two quite small fragments, though these are not phosphates.

Page 188 note 2 Damour, A., Extraits des procès-verb. Soc. Philomathique de Paris, 1852, p. 15 Google Scholar; Bull. Soc. Géol. France, 1856, ser. 2, vol. 18, p. 546; Hussak, E., Os satellites do diamante, Rio de Janeiro (Serviço Geol. Min. Brazil), 1917, p. 11 Google Scholar.

Page 188 note 3 An alleged occurrence in Tasmania, mentioned in the 1st (1893) and 2nd (1896) editions of W. F. Petterd's Catalogue of the Minerals of Tasmania, is omitted in the 3rd edition of 1910. G. Cesàro, Bull. Acad. R. Belgique, 1922, p. 559, mentions a crystal of euclase from Katanga, Belgian Congo.

Page 188 note 4 IIussak, E., Tsch. Min. Petr. Mitt., 1892, vol. 12, p. 473 Google Scholar; Os satellites do diamante, Rio de Janeiro (Serviço Geol. Min. Brazil), 1917, p. 43.

Page 188 note 5 Koechlin, R., Tsch. Min. Petr. Mitt., 1905, vol. 24, p. 329 Google Scholar.

Page 188 note 6 Kolbeck, F. and Henglein, M., Centralblatt Min., 1908, p. 335 Google Scholar.

Page 188 note 7 Bücking, H., Centralblatt Min., 1908, p. 425 Google Scholar. Dürrfeld, V., Zeits. Kryst. Min., 1909, vol. 46, p. 591 Google Scholar ; 1910, vol. 47, p. 245.

Page 191 note 1 Sponcer, L. J., Curvature in crystals. Min. Mag., 1921, vol. 19, pp. 263274, (see fig. 1, p. 266).CrossRefGoogle Scholar

Page 192 note 1 Damour, A., Note sur la présence du platine et de 1'érain métallique dans les terrains aurifères de la Guyane. Compt. Rend. Aead. Sei. Paris, 1861, vol. 52, p. 688 Google Scholar.