Zaffre

Description

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

Resources and Citations

• 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