19Th C. Viennese Enamel Jewelery Box. Measures H; 8 1/4" W 4 3/4" Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate 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 vitreous coating. The word comes from the Latin vitreum, meaning "glass".Enamel can be used on metal, glass, ceramics, stone, or any material that will withstand the fusing temperature. In technical terms fired enamelware is an integrated layered composite of glass and another material (or more glass). The term "enamel" is most often restricted to work on metal, which is the subject of this article. Enamelled glass is also called "painted", and overglaze decoration to pottery is often called enamelling. Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate 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 vitreous coating. The word comes from the Latin vitreum, meaning "glass".Enamel can be used on metal, glass, ceramics, stone, or any material that will withstand the fusing temperature. In technical terms fired enamelware is an integrated layered composite of glass and another material (or more glass). The term "enamel" is most often restricted to work on metal, which is the subject of this article. Enamelled glass is also called "painted", and overglaze decoration to pottery is often called enamelling.