Both green Depression glass and Vaseline glass will glow under a black light due to the uranium oxide content in the glass. Due to the presence of uranium oxide in the glass, the glass will glow a bright green color when put under a black light- this is the best way to identify it. Uranium, fluorescent and Vaseline Glass. Vaseline glass is a type of Uranium glass – glass with trace amounts of uranium added to color the glass. 1930-1950s. In this article Fluorescent Glass and Uranium Glass are defined very simply as any kind of glass which has uranium in it. American colorless pressed glass made before 1930 is said to fluoresce yellow, while reproductions generally do not.. While uranium is radioactive, it isn’t actually bad to drink or enjoy food in the glassware that uses this. I have avoided the term "Vaseline Glass" because there are conflicting interpretations of what it means. The leading company was Northwood but custard was also made by Heisey, Tarentum, Dithridge, U.S. Glass… Custard glass is a creamy pale yellow opaque glass (mostly pressed) made primarily in America, ca. This is Vaseline glass and is made by adding 2 percent uranium dioxide to the glass ingredients. The rise of pressed glass made it possible to mass-produce glassware, leading to the creation of some of the most recognizable styles including carnival glass, elegant glass, milk glass, crystal glass, and Depression glass. A community developed to share information on uranium glass - what it is and what it looks like, as well as how to hunt it, identify it, photograph it, and display it. Usually, the trace levels of uranium are at around 2%, but in some glass pieces from the 20th century, up to 25% of the material is made up of uranium. Confusing Custard Glass. The vases rest on a Vaseline glass base. This is called Burmese glass, because its color reminds the sunset of Burma country. Photo via Dave Peterson at VaselineGlass.org Top: The relationship between a piece of glass’s propensity to glow and its uranium content is often not predictable. Watch for glass that is yellow-green in appearance and looks slightly iridescent. Uranium glass is a type of glass that has uranium, usually in the form of oxide diuranate, added to the mixture before melting. This process adds colour to the glass. This practice dates back to the early 1800’s, and reached its height of popularity from the mid to late 1800’s up until the beginning of World War II. Mary Gregory Glass Identification Guide + Gallery. Pamela Wiggins. The piece at left contains no uranium at all, while the dark piece at bottom-center contains the most of the group. 1895-1910 then again as kitchen glassware, ca. Either red/orange fluorescence or blue/greenish-blue fluorescence means NOT vaseline glass.. 6) Opaque pink uranium glass (Burmese glass) Left hand cat looks pink with slightly green under sun light. 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