PLUMOSE GREY ANTIMONY-ORE. 481 It is opaque. It is very soft, passing into soft. It is rather brittle. It is easily frangible. Chemical Characters. Before the blowpipe, it melts into a black slag, after giving out a vapour, which, when condensed, appears in form of a white and yellow powder. Constituent Parts. According to Bergman, it is a compound of Anti- tnony, Sulphur, Arsenic, Iron, and Silver. Geognostic Situation. It occurs most frequently in veins in primitive rocks, that contain ores of silver, particularly white silver-ore; also in antimony veins. It is usually accompanied with argentiferous arsenicul-pyrites, native tellurium, and the ores, already mentioned as accompanying the other ores °f this metal. A newer formation is met with in transi tion rocks, where it is associated with galena or lead- glance, grey copper-ore, sparry ironstone, and fluor-spar. It Geographic Situation. Europe. It occcurs at Andreasberg and Clausthal in the Hartz; Frey berg and Braunsdorf in the kingdom of Saxony ; llathhausherg in Gastein, and Schwarzleogang * n Salzburg ; Schemnitz in Hungary ; Nagyag and Fel- *obanya in Transylvania. -America.—Mexico. Vol. III. 3. Nickeliferous