n. a deep blue pigment made from powdered glass mixed with cobalt oxide
the GNU version of the Collaborative International Dictionary of English
n. 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.
The Century Dictionary and Cyclopedia
n. Common glass tinged of a fine deep blue by the protoxid of cobalt.
Word Usage
""smalt" blue forget-me-not with large flowers were abundant, also an oxalis very like our own wood-sorrel."