A riza (Russian: риза, "robe") or oklad (оклад, "covered"), sometimes called a "revetment" in English, is a metal cover protecting an icon. It is usually made of gilt or silvered metal with repoussé work and is pierced to expose elements of the underlying painting. It is sometimes enameled, filigreed, or set with artificial, semi-precious or even precious stones and pearls. Although the practice of using rizas originated in Byzantine art, the Russian term is often applied to Greek icons; in Greek the term is επένδυση ("coating"). Icons are described as επάργυρες or επίχρυσες: silver-covered and gold-covered, respectively.