Cobalt on Trial
Cobalt oxide and cobalt carbonate are ceramic raw materials widely used by potters. They are frequently found in glaze and slip formulas contributing, under varied circumstances, a light to dark blue color depending on the amount employed. Cobalt has traditionally been used as a decorative blue colorant in everything from Chinese porcelain to American salt glazed stoneware. However, its use today reflects a wider problem potters face when employing any ceramic raw material. The dilemma is not with the specific raw material but with the lack of pertinent health statistics relating to the effects of ceramic raw materials on potters.