Colored Glass
Color in glass is usually produced by using metallic oxides, like iron, manganese, copper, cobalt, tin, nickel, silver, and chromium. Some of the most commonly found types are listed below.
Opaque Glass – White opaque glass was produced by adding tin oxide to molten glass and was used as early as Roman times. Opaque white glass was used by Venetian glassmakers in the 16th century, but it was not used by English glassmakers until the first half of the 18th century. The opaque colors yellow, ivory, green, blue, turquoise, and black were developed in the late 1870s (Jones 2000:147).
Transparent Glass – Transparent glass allows light to pass through so that objects behind can be distinctly seen. Different transparent colors were developed at different times. Red was developed in late 1820s and became popular in 1880s (Jones 2000:147). Grass green was first made successfully in 1900 (Jones 2000:147).
Opalescent Glass – Typified by a milky white edge or a white raised pattern decorating a colored pressed glass vessel. Transparent glass is covered with a layer of colorless glass containing bone ash, arsenic, or other minerals. The opalescent effect is produced by re-heating parts of the vessel, which turn white. Many U.S. factories produced opalescent glass between 1880 to 1920.
Uranium Glass – Uranium glass began to gain popularity in the United States in the 1830s and continued in regular production until just before WWII. It varies in color from transparent yellow and green, to opaque and opalescent green, white, or pink. It contains a small amount of uranium and will glow green under shortwave and longwave UV light, regardless of the color of the glass.
References
2000 A Guide to Dating Glass Tableware, 1800 to 1940. Studies in Material Culture Research. Edited by Karlis Karklins. Society for Historical Archaeology.