The term ‘faience’ in this context will be used for glazed objects with a non-ceramic core, as defined in Ancient Egyptian Materials and Technology (Nicholson and Shaw 2000: 277). Faience consists of a mixture of silica (crushed quartz pebbles), alkali or soda and lime (Nicholson and Shaw 2000: 186—7). As a material, faience is manufactured by using one of three methods:
applicationThe first method involves the inclusion of soluble salts which are mixed with the silica; during firing the salts melt to form a glaze (Nicholson and Shaw 2000: 186—7). The second method involves placing a silica-core object in a vessel filled with powder, which then sticks to the surface of the object during firing (Nicholson 1998: 53; Brandt 1999: 170-87). Thirdly, the silica-core object can be dipped into the glaze or it can be applied in the same manner as the non-vitreous glaze of ceramic vessels. In the Roman period all faience, with the exception of a handful of early examples, seems to have simply been dipped into a glaze with some evidence of a secondary application to certain parts, normally in a different colour, by brush.