French opalescent glass, various makers

The descriptions of glass as "opalescent" or "opaline" are often used interchangeably by dealers and auction houses. At the upper end of the scale, opalescent / opaline glass can refer to the opal-like milky blue glass produced by Lalique and Etling. It also refers to the pressed glass mass produced in Britain and France from the 1840s with a milky white edge as sugar-basins, milk jugs and vases were made in great quantities for the mass market, and were sold at fairs along with Staffordshire figures and wooden dolls. A less common type of opalescent glass was made from two layers of glass blown into a mould.