Tracing Cobalt Sources from the Medieval World to early Industrial Society

The study of blue pigments has proven especially important in ancient materials research, as this colour has always been an essential part of human expression. Initially, rare naturally blue minerals were used, while the first artificially generated 'Egyptian blue' appears in the early 3rd m. BCE. From the 16th c. BCE there was another major way of producing a blue: glass coloured using compounds of especially cobalt. Cobalt is a critical metal today and has always been throughout history. Cobalt ores are not common, but as they almost always exist in the presence of multiple other elements they tend to have a characteristic “fingerprint“ of elemental or isotopic compositions that can link a pigment to an associated ore or factory. This makes blue pigments an ideal subject of scientific investigation of ancient objects. This project will inventory and characterize ancient cobalt sources, allowing pigments to be traced from their production site to finished objects, revealing implications for underlying long-distance exchange networks.

Keywords:lead isotopes, archaeometry, smalt, cobalt, pigment, porcelain, trace elements

Disciplines:Archaeological science, Inorganic geochemistry, Geoarchaeology