What is glass made of?

Glass art includes the creation of stained glass, working glass in a torch flame (lampworking), glass beadmaking, glass casting, glass fusing, and the making of glass shapes through glass blowing. It dates back to prehistoric times, was extensively developed in Egypt and Assyria, brought to the fore by the Romans, and had its greatest triumphs in European cathedral building in stained glass rose-windows. Great ateliers like Tiffany, Lalique, Daum, Galle, the Corning schools in upper New York state, and Stubbe glassworks took glass art to the highest levels. Murano glass has not kept pace with production, but is still home to more glass masters than any other single place on Earth.