Plique-à-jour is a related enameling technique which uses clear enamels and no metal backplate, producing an object that has the appearance of a miniature stained glass object - in effect "cloisonné" with no backing. Plique-a'-jour is usually created on a base of mica or thin copper which is subsequently peeled off (mica) or etched away with acid (copper). In the Renaissance the extravagant style of pieces effectively of plique-à-jour backed onto glass or rock crystal was developed, but was never very common.