Grog (clay)
Type of temper used in clay / From Wikipedia, the free encyclopedia
Grog, also known as firesand and chamotte, is a raw material usually made from crushed and ground potsherds, reintroduced into crude clay to temper it before making ceramic ware. It has a high percentage of silica and alumina.
It is normally available as a powder or chippings, and is an important ingredient in Coade stone.