Published online by Cambridge University Press: 14 March 2018
Examples of quartz twinned on a face of the primary rhombohedron R are extremely rare. Only three isolated examples have so far been recorded. The first was observed by Q. Sella; but as his crystal could not be measured, owing to its position on the matrix, it is of only slight importance as evidence of this mode of twinning of quartz.
Page 112 note 1 Sella, Q., Mem. Accad. Sci. Torino, 1858, ser. 2, vol. xvii, p. 821 Google Scholar.
Page 112 note 2 Rose, G., Ann. Phys. Chem. (Poggendorff), 1851, vol. lxxxiii, p. 461 Google Scholar.
Page 112 note 3 Heauenberg, F., Neues Jahrb. Min., 1854, p. 806 Google Scholar; Eck, H., Zeits. Doutach. Geol. Gas., 1866, vol. xviii, p. 428 Google Scholar; Frenzel, A. and vom Rath, G., Ann. Phys. Chem. (Poggendorff), 1875, vol. clv, p. 17 CrossRefGoogle Scholar.
Page 112 note 4 Hintze, C., ‘Handbuch der Mineralogie,’ 1905, vol. i, p. 1857 Google Scholar.
Page 113 note 1 Goldschmidt, V., ‘Quarzzwilling nach r = 10,’ Min. Petr. Mitt. (Tschermak), 1905, vol. xxiv, pp. 157–166 CrossRefGoogle Scholar.
Page 113 note 2 Goldschmidt, V., ‘Über die Zwillingsgesetze des Quarz,’ tom. cit., pp. 167–182 Google Scholar.
Page 113 note 3 Michel Lévy, A., ‘Sur le porphyre bleu de l'Esterel,’ C. R. Soc. Géol. France, 1896, pp. xlvii–xlix Google Scholar ; and Bull. Serv. Carte Géol. France, 1897, vol. ix, no. 57, pp. 1-47, pls. I-VIII.
Page 114 note 1 Friedel, O., Bull. Soc. franç. Min., 1902, vol. xxv, p. 112 Google Scholar.
Page 116 note 1 Goldsehmidt, V., ‘Über Quarz,’ Zeits. Kryst. Min., 1908, vol. xliv, pp. 407–416 Google Scholar.
Page 116 note 2 Sella, Q., Mem. Accad. Sci. Torino, 1858, vol. xvii, p. 823 Google Scholar.
Page 117 note 1 Jenzsch, G., Ann. Phys. Chem. (Poggendorff), 1867, vol. cxxx, p. 597 CrossRefGoogle Scholar ; 1868 vol. cxxxiv, p. 540.