Uranium glass is a type of glass that has uranium, usually in the form of oxide diuranate, added to the mixture before melting. This is called Burmese glass, because its color reminds the sunset of Burma country. The leading company was Northwood but custard was also made by Heisey, Tarentum, Dithridge, U.S. Glass… Old Burmese glass fluoresces a similar yellow-green color. 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. 1930-1950s. Both green Depression glass and Vaseline glass will glow under a black light due to the uranium oxide content in the glass. Pamela Wiggins. 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. This process adds colour to the 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. Vaseline glass can be identified by shining a black light, or ultraviolet light, on the glass, which will glow florescent green. Vaseline glass is a type of Uranium glass – glass with trace amounts of uranium added to color the glass. 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. 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. In this article Fluorescent Glass and Uranium Glass are defined very simply as any kind of glass which has uranium in it. Custard glass is a creamy pale yellow opaque glass (mostly pressed) made primarily in America, ca. 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. The vases rest on a Vaseline glass base. This is Vaseline glass and is made by adding 2 percent uranium dioxide to the glass ingredients. Also, we like to oooh and aaah over glowy glass! Mary Gregory Glass Identification Guide + Gallery. Uranium, fluorescent and Vaseline Glass. Back to Glass Encyclopedia Home. I have avoided the term "Vaseline Glass" because there are conflicting interpretations of what it means. Watch for glass that is yellow-green in appearance and looks slightly iridescent. The term 'Mary Gregory' indicates a style of glass rather than a manufacturer.It originates from the myth that a lady in USA named Mary Gregory painted scenes of children on thousands of items of glassware. Above: Flower vases made at the Thomas Webb & Sons factory in England. The fluorescence of vaseline (uranium) glass is always green. 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. 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. Above: Two green uranium glass vases by Sowerby of Gateshead, made in the 1930's. Confusing Custard Glass. 1895-1910 then again as kitchen glassware, ca. The piece at left contains no uranium at all, while the dark piece at bottom-center contains the most of the group.