\Co"balt\ (k[=o]"b[o^]lt; 277, 74), n. [G. kobalt, prob.
fr. kobold, kobel, goblin, MHG. kobolt; perh. akin to G.
koben pigsty, hut, AS. cofa room, cofgodas household gods,
Icel. kofi hut. If so, the ending -old stands for older
-walt, -wald, being the same as -ald in E. herald and the
word would mean ruler or governor in a house, house spirit,
the metal being so called by miners, because it was poisonous
and troublesome. Cf. {Kobold}, {Cove}, {Goblin}.]
1. (Chem.) A tough, lustrous, reddish white metal of the iron
   group, not easily fusible, and somewhat magnetic. Atomic
   weight 59.1. Symbol Co.
Note: It occurs in nature in combination with arsenic,
      sulphur, and oxygen, and is obtained from its ores,
      smaltite, cobaltite, asbolite, etc. Its oxide colors
      glass or any flux, as borax, a fine blue, and is used
      in the manufacture of smalt. It is frequently
      associated with nickel, and both are characteristic
      ingredients of meteoric iron.
2. A commercial name of a crude arsenic used as fly poison.
{Cobalt bloom}. Same as {Erythrite}.
{Cobalt blue}, a dark blue pigment consisting of some salt of
   cobalt, as the phosphate, ignited with alumina; -- called
   also {cobalt ultramarine}, and {Thenard's blue}.
{Cobalt crust}, earthy arseniate of cobalt.
{Cobalt glance}. (Min.) See {Cobaltite}.
{Cobalt green}, a pigment consisting essentially of the
   oxides of cobalt and zinc; -- called also {Rinman's
   green}.
{Cobalt yellow} (Chem.), a yellow crystalline powder,
   regarded as a double nitrite of cobalt and potassium.