glazed composition (Scope note)

The term is used for objects with a body made of finely powdered quartz grains fused together with small amounts of alkali and/or lime through partial heating. The bodies are usually colourless but natural impurities give them a brown or greyish tint. Colourants can also be added to give it an artificial colour. It can be modelled by hand, thrown or moulded, and hardens with firing. This material is used in the context of Islamic ceramics where it is described as stonepaste (or fritware). Glazed composition is related to glass, but glass is formed by completely fusing the ingredients in a liquid melted at high temperature. This material is also popularly called faience in the contexts of Ancient Egypt and Ancient Near East. However, this is a misnomer as these objects have no relationship to the glazed pottery vessels made in Faenza, from which the faience term derives. Other authors use the terms sintered quartz, glazed frit, frit, composition, Egyptian Blue, paste or (in the 19th century) even porcelain, although the last two terms are very inappropriate as they also describe imitation gems and a type of ceramic. Frit is technically a flux.