Overlay glass is glass made with one or more outer layers of coloured glass over a base of clear or differently coloured glass, which are then cut or engraved through to reveal the colours beneath. The term is often used interchangeably with cased glass, although overlay is usually applied when the outer layer has been decoratively cut away.
The technique reached a high point in Bohemia in the second quarter of the nineteenth century, where glassmakers produced vases, goblets, scent bottles and lustres with ruby, blue, green or white overlays cut with windows, panels and floral designs. White overlays were often further enriched with enamel painting and gilding. British factories in Stourbridge and elsewhere also produced fine overlay glass, and the method led directly to the carved cameo glass of the later Victorian period. Double overlay glass, with two contrasting layers, is particularly prized. Collectors look for crisp, even cutting, strong colours, good gilding and an absence of chips to the fragile edges of the overlay. Lamps, lustres and vases in overlay glass catch the light beautifully and remain popular for decorative display on chimneypieces and side tables.
