Refers to cut crystal glass in which a decorative ceramic object is embedded, usually a medallion or cameo that has been carved into a white porcellaneous, heat-resistant material. A Bohemian invention of the 18th century, the technique was taken up in Paris but only became popular through English glassmakers in 18th- and 19th-century Europe. For glass characterized by a particular yellow or red color, use "cadmium sulphide glass."