Gunson’s Glowing Glass: History and Archaeology of Uranium Glass

Over the summer, we found some yellow-green bumpy glass within the Gunson collection. It was a unique color that didn’t fit with the normal range of aqua, clear, green and brown glass, and appeared to be in a form that was nicer- like a vase or drinking glass. It also had an odd raised pattern that we hadn’t seen before.

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Our vaseline glass in normal light

That’s when we pulled out the black light and discovered it glowed! We had found our first sample of Uranium Glass on campus.

Our vaseline glass under black light

Our vaseline glass under black light

Uranium glass, also known as vaseline glass due to its color, is glass that has uranium added to the mixture during the molten period when color is added. The amount of uranium can range from 2-20%, and can vary in color from yellow to yellow green or even avocado coloring. 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. While uranium is radioactive, it isn’t actually bad to drink or enjoy food in the glassware that uses this. The amounts that leach out of the glass is so tiny, that it won’t have an effect on you.

Vaseline glass became popular during the mid-19th century, and was at its height of popularity from the 1880s to 1920s. Uranium oxide was first used as a coloring agent in the 1830s, and spread throughout Europe during the 1840s. It was produced by a variety of companies, who specialized in different tones of greens and yellows. Each company had unique names for their specific color of uranium glass, including citron, jasmine, golden green, mustard, Florentine and more. During the Depression, iron oxide was added to the glass to increase its green glow- although antique collecting purists argue that this shouldn’t be included in true uranium glass collections. The glass was formed into a variety of decorative and practical dinnerware pieces including cups, bowls, plates, vases, figurines, paperweights and more.

In 1943, production of vaseline glass was stopped due to the implementation of heavy regulations on the use of uranium. It wasn’t until 1958 that uranium was deregulated and the production of vaseline glass resumed, this time using depleted uranium instead of the natural radioactive version.

Vaseline hobnail glass bowl - our fragment is likely from the base. Image Source

Vaseline hobnail glass bowl – our fragment is likely from the base. Image Source

At the Gunson/Admin site, our uranium glass included a piece of golden green hobnail glass. Hobnail glass is a specific pattern of decoration where bumps of glass are added to the exterior or interior of the glass to produce a raised pattern. While these were most popular during the 1940s and 1950s, they came into production during the Victorian period. Our uranium glass is a unique piece of history, and is just plain cool. The glowing glass is something that today we may view as strange- who would ever want to drink out of a glass colored with a radioactive material- but in the past was a unique collectible. You can still find examples of uranium glass today in antique shops, but buyer beware. There are fake vaseline glass products that have the neon green coloring but do not glow under a black light. Unless it glows, it isn’t real uranium glass!

References

Antique Vaseline Glass. Collector’s Weekly. http://www.collectorsweekly.com/glassware/vaseline-glass

These People Love to Collect Radioactive Glass. Are They Nuts? Collector’s Weekly. http://www.collectorsweekly.com/articles/these-people-love-to-collect-radioactive-glass/

Uranium Glass. Wikipedia. https://en.wikipedia.org/wiki/Uranium_glass

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