Stemmed Goblet, probably Stevens & Williams, Ltd., possibly Thomas
Webb and Sons, 1875-1925. Gift of Thomas P. Dimitroff. 2004.2.11.
Flashed glass is made by putting a thin layer of glass over the initial layer. It is usually colored glass that is the outer (second) layer. If the first gather was colored, and the second/outer layer was clear, the object's appearance would be quite different than creating clear and then colored layers. The goblet on the right, for example, was colorless glass flashed with amnesty (manganese) glass. This website on Flashed Glass provides more information and images of flashed glass.
