INDURATED BLACK COBALT-OCHRE. botryoidal, small renlform, fruticose, corroded, and with impressions. The surface is feebly glimmering. Internally it is dull, or very feebly glimmering. The fracture is fine earthy, sometimes passing into conchoidal. The fragments are indeterminate angular, and blunt- edged. It sometimes occurs in thin and curved lamellar dis tinct concretions. The streak is shining and resinous. , It is very soft, approaching to soft. It is sectile. It is very easily frangible. Specific gravity, 2.019 to 2.425 Gellert; 2.9287, Kopp. Chemical Characters. Before the blowpipe it gives an arsenical odour, and colours glass of borax smalt-blue. Constituent Parts. It is considered as black oxide ot cobalt, with arsenic and oxide of iron. Geognostic Situation. ‘ Both subspecies usually occur together, and in the Sa me kind of repository ; but the first subspecies is the rarest. They are found sometimes in primitive moun tains, but most frequently in lloetz mountains, where they are accompanied with ochry-brown ironstone, red, brown, and yellow cobalt-oehres, native-silver, several other