120 COPPER. 4. Those varieties which contain the largest propor tion of sulphur, are the least affected by exposure to the 5. White Copper-Ore. Weiss Kupfererz, Werner, Weisslich Kies-kupfererz, Henkel's Kieshistorie, s. 210—Mi ners Cupn alba. Wall. t. ii. p. 280—Weiss Kupfererz. Wer. ner, Pabst. b. i. s. 83. Id. Wid. s. 750.—White Copper-ore, Kirw vol. n. p. 152—Weiss Kupfererz, Estner, b. iii. s. 505. Id. Emm. b. ii. s. 286-Mine de Cuivre blanche arsenicale, am ' P- 201 —La Mine de Cuivre blanche, Broch. t. ii. p. 173. Weiss Kupererz, Hems, b. iii. s. 425. Id. Lud b i /' T'/f f UCL 2t6r th ‘ S ‘ M BerL s - 397. Id. Leon. w! S ' 58 ' Id ' Kurslen > Tabel. s. 62. Id. Ilaus. s. 74—White Copper, Aik in, p. 28. External Characters. Its colour is intermediate between silver-white and bronze-yellow, winch sometimes inclines slightly to brass- yellow. On the fresh fracture, it soon becomes tarnish ed with a greyish-yellow colour. It occurs massive and disseminated *. InternaHy it i s glistening, with a metallic lustre. 1 he fracture is small and fine-grained uneven. It sometimes occurs in curved lamellar concretions, the surfaces of which are splendent and metallic. 1 he fragments are indeterminate angular, and rather sharp-edged. It is soft, passing into semi-hard. It * According to Karsten and Ullman, it occurs crystallised in octahedrons