Sulphides are cameos of unglazed white porcelain encased in transparent glass. The technique was patented in 1819 in France and has been used ever since for paperweights, decanters, tumblers, marbles, and other type of glassware. Suphide paperweights were made by Baccarat, Cristal d'Albert, St. Clair, and others. Paperweights and Marbles are listed in their own categories. For more information, explore our identification guides for glass, marbles, and paperweights.