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200 SULPHIDES. a 100 cleavage, o ill. PIO. 199. ad 90° o' 00 70 32 Od 64 44 Cleavage, a, imperfect. Fracture uneven. Opaque. Lustre metallic. Lead-grey. Streak grey, shining. Sec- tile. H = 2-5. G = 6-833. In the matrass decrepitates and falls into powder. Before the blowpipe on charcoal emits sul phurous acid fumes and deposits a sublimate of oxide of anti mony upon the charcoal, and after prolonged exposure to the flame leaves a globule of lead, which by cupeflation yields a globule of silver. J LbjSb, sulphides of lead and antimony in unknown propor- In botryoidal and reniform masses, the surfaces of which are studded with crystals. Is found at Przibram in Bohemia with silver, blende, pyrito and quartz. 89. BERTHIERITE.—Berthierite ; Dufrenoy. Berthierit; Mohs, Hausmann, Haidinger. Cleavage in several directions, indistinct. Fracture uneven. Opaque. Lustre metallic. Iron-black, dark steel-grey, inclin- ing to yellowish or reddish; liable to tarnish, h = 2-o...3 p o. g = 4-0. ..4-3. Before the blowpipe on charcoal melts readily, yields fumes of antimony, and leaves a black magnetic slag. Soluble in hydrochloric acid, more readily in nitromuriatic acid. FeSb, iron 12'30, antimony 58-61, sulphur 29-19. Analyses of berthierite a from Chazelles, b from Martouret mine in Auvergne, c from Anglar, all by Berthier; d, e from -tsraunsdorfby Eammelsberg,yfrom Arany-Idka by v. Pettko: Iron . . Zinc . . Manganese Antimony Sulphur . a b C d e / 160 9’85 12-17 11-96 11-43 1285 0-3 — — trace 074 — — •— 0-46 2'64 620 61-34 68-65 64-34 64-70 67*88 30'3 28-81 2918 80-67 3133 29*27