An impure form of cobaltous oxide obtained by roasting native cobalt ores (cobaltite, smaltite). Zaffre is used to manufacture smalt, a blue pigment. Smalt is the fused product of finely ground zaffre (cobaltous oxide) mixed with potassium silicate (glassmakers fine white sand). Zaffre is also used directly as a pigment in enamels and ceramics (Mayer 1969). Cobalt oxide is used to give a blue color to structural glass, bottles, and optical filter glasses. It is also used to minimize the yellow tint from iron impurities in window glass.
Synonyms and Related Terms
zaffer; zaffir; zaffar; saffer; saffre; cobaltous oxide; cobalt oxide
R. Mayer, A Dictionary of Art Terms and Techniques, Harper and Row, New York, 1969.
Sources Checked for Data in Record
- Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
- Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985