Enamel is produced by fusing coloured powdered glass paste to metal (usually silver, copper or gold) to produce a glass-like, decorative surface. The colour of the enamel and its transparency depends on the metal oxides in the glass and the temperature at which the glass melts. In some cases, the enamel may be translucent showing the textures of any engraving on the metal underneath, which produces guilloche (pronounced ghee-yosh) enamel.