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ILMEHITE. 239 mitted tlirougli a red-hot tube, the vapour is decomposed into chlorine, oxygen and oxide of chrome, -fir, chrome 69'99, oxygen 30-01, which is deposited on the interior of the tube in small twin crystals, the individuals of which resemble the combina tion oran (fig. 254) of hematite, with which, ilmenite and corundum, it is isomorphous, having very nearly the same angles. In these crystals rd = 94° s'. The twin face is r. They have a perfect cleavage parallel to the faces r. Lustre metallic, inclining to adamantine. Greenish-black. Streak bright green. H = 9'0. G = 6'21. When a six-sided crystal of hematite was placed in the tube, the oxide of chrome was deposited upon the crystal of hematite with the faces and cleavages of the latter parallel to those of the former, as hap pens frequently in other cases, when crystals of one of two iaomorphous bodies are deposited upon a crystal of the other. 124. ILMENITE.—Fer oxidule titane; Hauy. Axotomes Eisen-Erz ; Mohs. Kibdelophan; Iiausmann. Ilmenit, Crich- tonit; Ilaidinger. Rhombohedral. 100,111 = 57° 30'. 0 111, a oil, b 21I, I in, r 100, e oil, s 111, £ 311, P 322, n 13I, x 164. ( truncates the edge or. The forms x are frequ ently hemihedral with parallel faces. aal 60° 1 o' eo 38° 7' rr r 93° 50' IV 120 0 so 72 20 ss ill 13 la' 30 0 po 84 44 pp' 118 26 ah’ 30 0 ao 90 0 ed 46 55 bo 90 0 xo 77 33 sd 55 36 lo 75 42 no 61 7 nn 51 56 ro 57 30 cc 54 50 nd 25 68 (0 32 7 ed 64 38 EXG. 259. EIG. 260. FIG. 261. Combinations, or, ora, ore, orri, oers, oersn, olerma, op, opl, °P}a, oplax'. The faces 0 striated parallel to their intersections with r. Twins. Twin-face 0. Cleavage. 0, more or less per-
