Enamel (glass)
Enamel is made of melted glass, often on metal. Sometimes called vitreous or porcelain enamel, it is made by fusing powdered glass to a base by firing, usually between 750 and 850 °C (1,380 and 1,560 °F). The powder melts, flows, and then hardens to a smooth, durable coating on metal, or on glass or ceramics.