In glassworking, the process of coloring the surface of glass by the application of silver sulfide or silver chloride, which is then fired at a relatively low temperature. The silver imparts a yellow, brownish yellow, or ruby-colored stain, which can be painted, engraved, or etched.

(1) Several types of glass with newly developed surface textures, shaded colors, or casing, made in the United States from about 1870 and in Europe between about 1880 and 1900; (2) more generally, especially when written “art glass,” any ornamental glassware made since the mid-19th century.