Rolled opal glass (type of glass ranging from complete opacity through various grades of translucency) with a naturally hard, brilliant, fire-finished surface, first made in England in 1930. It was manufactured in black and white and a range of standard colours which were inherent in the glass, and was employed in cladding as in a curtain-wall (4), usually in panels beneath panels of clear glass, e.g. Owen Williams's Daily Express building, Fleet Street, London (1932). It was also used to clad the dado of the Mersey Tunnel (1934), replaced with cream Vitrolite in 1954–5.
McGrath & Frost (1937).