Enameling

Ancient Egyptians created a precursor to the enameling process by embedding decorative glass into gold objects. The first examples of the modern enameling process, by which molten glass is fused to the surface of certain metals, was discovered in Greek gold jewelry dating from the 4th century BC. From this point forward, enameling was practiced by many cultures.

Enamel is a decorative technique by which glass compounds are applied to the surface of metal and is fused under high temperatures. This process is only suitable for metals resistant to thermal expansion such as silver gold, and copper. The extreme expansion of more vitreous metals would cause any enamel applied to crack during the cooling process.

The metal oxides that exist in the glass and the temperature at which the glass is fused to the surface affect the appearance of enamel. Generally, enamel that is fused at higher temperatures is more durable, and more translucent, while enameling fired at lower temperatures is softer, more fragile, and more opaque.