The microstructure and chemical composition of a range of early vitreous materials, principally from Egypt and dating from mid‐second millennium B.C. onwards, have been examined in polished section in a scanning electron microscope with attached X‐ray spectrometer. Faience is defined as a material with a quartz core which contains varying amounts of interstitial glass and which is covered with alkali‐based coloured glaze and frit as a polycrystalline material which is coloured throughout and has no glaze covering. The amount of interstitial glass and hence the chemical compositions of the faience cores depends on the methods of production used. Frits which, on the basis of the above definition, include Egyptian blue and glassy faience differ from faience cores in containing significantly higher concentrations of lime and copper oxide. The nature of the frit, including its colour, depends on the relative amounts of lime and copper