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GEHLEUITE. 379 215. BARSOWITE.—Barsowit; Hausmann, Haidinger. Cleavage in one direction tolerably perfect. Fracture splin tery. Translucent on the edges. Lustre pearly...dull. White. H = 6-3...6-0. G = 2'74...2-752. Before the blowpipe melts with difficulty on the edges into a blebby glass. With borax melts into a colourless transparent glass. With salt of phosphorus leaves a skeleton of silica. With solution of cobalt turns blue. Is easily decomposed by ''rarm hydrochloric acid forming a jelly of silica. APSi 3 -f 2CaSi, part of the Ca being replaced by Mg. Analyses by Varrentrapp :— Silica 49’01 49'05 48'07 Alumina 33'85 33'78 34-08 Lime 15-40 15-30 15-10 Magnesia 1"56 i"42 1'65 Is found in granular and compact masses, in blocks containing corundum, spinelle and mica, in the auriferous sand of Bar- sowskoi near Kyschtimsk in the Ural. 216. GEIILENITE.—Gehlenito ; Phillips, Hauy. Pyra- midaler Adiaphan-Spath ; Mohs. Gchlenit; Hausmann, Hai dinger. Pyramidal. FI& - 394 - « 100, c 001. c a ac 90° o' ad 90 o Cleavage, c, imperfect, but distinct; a, traces. Fracture imperfect eonchoidal...uneven. Faces rough, uneven. Trans lucent on the edges. Lustre resinous, inclining to vitreous. Grey, brown, green. Streak white. Not very brittle, ii = 5 '6...eo. o = 2-99. ..810. Before the blowpipe fusible in thin splinters with great difficulty. With borax and salt of phosphorus fuses into a glass coloured by iron. Is completely decomposed, both before a 'id after ignition, by warm hydrochloric acid, forming a jelly of silica. C
