Smalt \Smalt\, n. [It. smalto, LL. smaltum; of Teutonic origin; cf. OHG. smalz grease, butter, G. schmalz grease, OHG. smelzan to melt, G. schmelzen. See Smelt, v. t., and cf. 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.

Source: Webster's Revised Unabridged Dictionary (1913)