Plique-à-jour (French for "letting in daylight") is a vitreous enameling technique where the enamel is applied in cells, similar to cloisonné, but with no backing in the final product, so light can shine through the transparent or translucent enamel. It is in effect a miniature version of stained-glass and is considered very challenging technically.
This beautiful pair of earring is hand crafted from fine silver and vitreous enamel, using this ancient technique.
