Volltext Seite (XML)
304 SILICATES. The titanic acid in b is derived from a mechanical mixture of ilmenite. Arfvedsonite is found in cleavable masses in a crystalline slate rock at Kangerluardsuk in Greenland, with sodalite, eudialyte, felspar and mesotype. Also in the south of Norway in zirconsyenite mingled with krokydolite, and in the beds of iron ore at Arendal. The arfvedsonite in Mr. Brooke’s collec tion is very fusible, melting in the flame of a candle without the aid of the blowpipe. Hence there can be but little room for the doubt entertained by Breithaupt as to its identity with the mineral analyzed by v. Kobell. 169. BABINGTONITE. ■—Babingtonite; Phillips, Beu- dant. Axotomer Augit-Spath; Mohs. Babingtonit; Haus- mann, Haidinger. Anorthic. 011,010 = 67° 5l', 001,010=87° 26', 210,010 = 42° 56', 100,010 = 67° 30', 001,100 = 92° o'. a ioo, b 010, 0 001, d Oil, h 210, bo O L- 00 26' 0 47° 45' ca 92 0 ha 24 35 ab 67 30 do 29 35 hb 42 65 db 67 61 FIG. 319. V Combinations, cbhg, cbahgd. a, b, h, g striated parallel to their intersections with each other, c, d striated parallel to their intersections with I. Cleavage, c, perfect; a, less per fect. Practure imperfect conchoidal. In thin fragments trans lucent. Lustre vitreous. Black. By transmitted light, brownish in a direction perpendicular to c, greenish in directions parallel to c. Streak greenish-grey. Brittle. 11 = 5 - 5...6-o. g = 3’355... 3-406. Before the blowpipe melts easily, with intumescence, into a brownish-black, bright, magnetic globule. Imparts the colour of iron to glass of borax. Is slowly decomposed by boiling hydrochloric acid. Analysis of babingtonite from Arendal a by Arppe, I by R- D. Thomson:— a b Silica 64-4 47-48 Alumina o’3 0-48