This is large pendant that converts to a brooch. It is about 50 x 40 mm in size. All hardware made out of solid 925 sterling silver. Fine silver wires were used for cloisonne.
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".