COBALT, a metallic element, at. wt. 59, symbol Co. The metal was first ob tained in an impure state by Brandt, in 1733. It occurs as speiss cobalt, or tin white cobalt CoAs,, and cobalt-glance, CoAsS. Cobalt occurs in meteoric iron. Metallic cobalt is a hard, magnetic, duc tile, reddish-gray metal, with a high melting point. Its sp. gr. is 8.9. It is not easily oxidized by the air, when pure. It is dissolved by dilute HC1 or H,SO, with evolution of hydrogen. Cobalt forms two oxides: Cobaltous oxide Co0 and Cobaltic oxide Co,O,. The alloys of cobalt are unimportant. Zaffre is an impure oxide of cobalt prepared by roast ing cobalt ores with twice their weight of sand. Smalt is prepared by fusing partially roasted cobalt ores with a mix sure of powdered quartz and potassium carbonate; while hot it is poured into water and then ground to a fine powder; it is used as a pigment; this color was known to the ancients. The cobaltous
salts are the most stable in which cobalt acts as a dyad element. Cobalt com pounds give a blue color to a borax bead.
There is no native cobalt known, but many ores of the metal. Arsenate or Ar seniate of Cobalt=Erythrite; Arsenical Cobalt= Smaltite; Black Cobalt=Asbo lite; Bright-white Cobalt=Cobalt-glance; Carbonate of Cobalt = Remingtonite; Earthy Cobalt=Asbolite; Gray Cobalt= Smaltite; Red Cobalt = Erythrite; Sul phate of Cobalt=Bieberite; Sulphuret of Cobalt=Syepoorite, Linnmite; White Co balt=Smaltite; Cobalt and Lead Sele nite=Tilkerodite.
Ammonia cobaltous salts are formed by the union of cobaltous salts with am monia in excess, the air being excluded, as, CoC12..N113, rose-colored crystals. They are formed when an ammoniacal solution of cobalt is exposed to the air.