smalt

noun

A deep blue paint and ceramic pigment produced by pulverizing a glass made of silica, potash, and cobalt oxide.

noun

Common glass tinged of a fine deep blue by the protoxid of cobalt.

noun

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.

noun

a deep blue pigment made from powdered glass mixed with cobalt oxide