cobalt yellow

Cobalt \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.
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   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.
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   2. A commercial name of a crude arsenic used as fly poison.
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   {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.
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