Smalt
Smalt , noun
[Italian smalto, Late Latin smaltum; of Teutonic origin; compare Old High German smalz grease, butter, German schmalz grease, Old High German smelzan to melt, German schmelzen. See Smelt, transitive verb, and compare Amel, Enamel.]
A deep blue pigment or coloring material used in various arts. It is a vitreous substance made of cobalt, potash, and calcined quartz fused, and reduced to a powder.