Volltext Seite (XML)
A‘* It : Tt r • ucr l yv : * 1 *-& “ wfi* ^ 624 IIXDEOUS HELLATE. The faces m are striated parallel to their intersections with u ; , /striated parallel to their intersections with each other. Twins. JTwin-face e. co = 38° 66', xx = 23° 22', ss = 51° 4', mm = 76° 4', X ?V lC f ' im — 48 ° 48', ff = — 21° 36'. Cleavage, c, m, J. Fracture C. -j. 1 conchoidal. Transparent... opaque. Lustre vitreous, inclining to adamantine. Colourless. Streak white. Very brittle. ; 5* fV H = 2*5.. .2*75. G = 1*833. Ca-G + H, oxalic acid 46*31, lime 38*36, water 12*33, accord- m ing to an analysis by Sandall. __ j In small attached crystals, mostly twins, with calcite. Is Ifa 7^ sll PP osec ^ *° ^ ave ^ een found in Hungary. HYDE01TS MELLATE. 459. MELLITE.—Mellite ; Phillips, Hauy. Pyramidales Melichron-IIarz; Mohs, Mellit; Hausmann, Haidinger. Pyramidal. 101,001 = 36° 44'. a 100, c 001, e : 101, r ill. ac 90 c > 0' ra 69° 7' ad 90 0 rc 46 33 ea 53 16 rr 61 46 ec 36 44 re 30 63 ee 50 2 rr 1 ' 93 6 Combinations, or, ra, era :, cera f FIG. 640. The faces c rough and curved; e rough. Cleav age. r, very difficult. Fracture con choidal. Transparent...translucent. Lustre resinous, inclin ing to vitreous, e = 1*638... 1*666. Honey-yellow, inclining to red or brown. Streak white. Sectile. it = 2*0...2*6. g = 1*6. ..1*6. In the matrass yields water, and carbonizes without emitting any perceptible smell. Before the blowpipe on charcoal burns white, leaving nothing but alumina. Completely soluble in nitric acid, in hydrochloric acid, and in caustic potash. A1C 4 O 3 + 1811, mellitic acid 40*31, alumina 14*35, water 46*34. Analysis of mellite from Artem by Wohler:— Mellitic acid 41*4 Alumina 14-5 Water