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254 OXIDES, EABTHS, AND ACIDS. FIG. 279. m 10° 2' ra 36 16 sa 64 46 rn 159 66 rr' 109 28 «*' 50 28 ma 68° 29' mm’ 43 2 Xa 52 49 xxf 74 22 Xx” 100 16 afx" 155 17 o' r 1 r a Combinations, sm, rma, rxma. The faces r, x curved; a, smooth and plane; m, sometimes rough, but plane. Cleavage. m, very perfect. Fracture not observable. Semitransparent... translucent. Lustre adamantine, especially on the curved faces; a, pearly. White, passing into grey, yellow, brown and red. Streak white. Sectile. h = 2 - 6...3'0. o = 5'566. In the matrass it sublimes completely. Melts very easily before the blowpipe, sublimes and forms a crystalline deposit on the charcoal. Is reduced in the inner flame, especially when mixed with soda and cyanide of potassium, and colours the flame green. With borax it forms a glass which is yellowish while hot, but becomes almost colourless on cooling. It is readily soluble in nitromuriatic acid. It is precipitated from the solution on the addition of water. Sb, antimony 84 - 32, oxygen 16'68. Analysis of valentinite from Wolfach by Suckow:— Valentinite occurs generally in tabular and acicular crystals, in diverging groups of crystals; more rarely in granular, co lumnar or lamellar masses; as a thin crystalline coating on other minerals; pseudomorphous after antimony. It is found at Przibram in Bohemia, Braunsdorf in Saxony, Pemek near Malaczka in Hungary, Wolfach in the Breisgau, Horhausen in Nassau, Allemont in Dauphind. Oxide of antimony is dimorphous. Octahedral as well as prismatic crystals are obtained in smelting some of the ores of antimony, and also from a solution of chloride of antimony in boiling carbonate of soda. When sublimed at a high tempera ture, the crystals belong to the prismatic system; sublimed at a low temperature, it crystallizes in octahedrons. A solution of antimonic oxide in boiling soda crystallizes in octahedrons on Oxide of antimony sb . . 917 Red oxide of iron . Silica 1-2 0-8 6-3 Antimony
