Mosaic glass, also known as smalti or tesserae, is a type of glass used in the creation of mosaics. It is composed of small pieces of colored glass that are cut into shapes and then arranged to form a pattern or image. The pieces are usually held together with mortar or grout. Mosaic glass is often used to create decorative artworks, such as wall murals, floors, and tabletops. Smalti is an Italian term for mosaic glass, while tesserae is a Greek term meaning 'small stones'.