COBACITE. 221 FIG. 228. 00 70 32 rracture conchoidal... uneven. Opaque. Lustre resinous. Pitch-black, greenish- black, greyish-black. Streak greenish- black. Brittle, n = 6 - 6. G = 8’4...0'7l. Infusible before the blowpipe. With borax and salt of phosphorus yields a yellow globule in the outer flame, and a green globule in the inner flame. Dissolves in hot nitric acid, forming a yellow solution. UIJ, uranium 81'78, oxygen 16'22, with from 20 to 24 per cent, of lead, bismuth, iron, arsenic, lime, magnesia, silica, water, and sometimes selenium and vanadium. Analyses of pechuran from Joachimsthal a by Eammelsberg, b by Ebelmen, c by Scheerer:— a Oxide of uranium u# . . 79'15 Lead 0-20 Lismuth with rb and Cu . 0'05 Iron 3'03 Arsenic ri3 Lime 2 p 8i Magnesia 0'40 Silica 630 M^ater o p 36 Mil Fe s Na 6 b 76-94 422 0-82 3’10 0-60 5*24 oxide of lead 2*07 metallic acids 3'48 silica 1-85 0*25 stony matter 3*32 and loss 70-6 10 166 410 \ 2'7 Is found at Johann-Georgenstadt, Wei sen that, Marienberg, Annaberg and Schneeberg in Saxony; at Joachimsthal and Przibram in Bohemia, associated with- torberite, and in the tin ttines of Tincroft and Tolcarn near Eedruth in Cornwall. 110. COEACITE.—Le Conte. Silliman’s Journal. 1847. 3. 173. Amorphous. Practure uneven. Pitch-black. Streak grey. II = 3-Q, Q _ 4'378. Unchanged before the blowpipe. With the fluxes gives the characteristic reactions of uranium. Eeadily soluble with effervescence in hydrochloric acid. The solution has a green colour. L 3