[Ger. kobalt; from kobold, a goblin.] A reddish-white metal, very tenacious, and very difficult to fuse; occurs in small quantities in meteoric stones, and is usually found combined with arsenic and sulphur. It forms three compounds with oxygen. One oxide imparts a deep -blue color to glass. This glass, reduced to powder, is used in producing the blue colors in porcelain, pottery, glass, encaustic tiles, etc. Chloride of cobalt diluted forms sympathetic ink.