Egyptian faience is a sintered-quartz ceramic displaying surface vitrification which creates a bright lustre of various colours, with blue-green being the most common. Defined as a “material made from powdered quartz covered with a true vitreous coating, usually in a transparent blue or green isotropic glass," faience is distinct from the partly crystalline compound Egyptian blue. Notably, faience is considerably more porous than glass proper and can be cast in molds to create vessels or objects. Although not properly pottery, as (until late periods) it contains no clay and instead contains the major elemental components of glass (silica), faience is frequently discussed in surveys of ancient pottery, as in stylistic and art-historical terms objects made in it are closer to pottery styles