Is Uranium Glass Safe To Facet?

“Uranium Glass” by UCL News is licensed under CC By-ND 2.0
“Uranium Glass” by UCL News is licensed under CC By-ND 2.0


A friend of mine was going through some old stuff in his attic and found something labelled “atomic glass.” Since it looked like a yellow gem, he gave it to me. (By the way, it’s preformed to a nice, big emerald cut). Any ideas what it could be? It’s heavy and seems to be leaded glass. What precautions should I take in cutting it? Any worries with fine mists, dusts, or anything like that? Another friend told me it might be a piece of glass from a nuclear testing site! Any guidance would be appreciated.

Test Your Uranium Glass Before Cutting

From your description, it sounds like you have a piece of uranium glass. I’m almost certain it’s not glass from a nuclear test site. (From what I know about the glass that was formed during nuclear detonations, you wouldn’t be able to find a gem-quality piece large enough to facet). When present in glass, uranium imparts a yellow color and makes it very heavy.

It would be a VERY BAD idea to cut uranium glass without knowing more about your piece. Most uranium glass is fairly innocuous, but some of it is quite radioactive. In fact, some of the “hotter” specimens are dangerous to even have around, let alone facet. It’s actually not the uranium that makes uranium glass dangerous but other elements found in the uranium ore.

“Uranium Glass” by Danilo Russo is licensed under CC By CC By-ND 2.0
“Uranium Glass” by Danilo Russo is licensed under CC By-ND 2.0

If you have a weird physicist friend who owns a Geiger counter or can get a local university to help, you can test your specimen to determine its radioactivity level. I wouldn’t mess with anything that was more than a couple of times more active than background radiation levels. The simplest thing to do, of course, is turn in your uranium glass specimen at the nearest household hazardous waste collection site and not take the chance.

If you want to facet glass, there are many different varieties of glass and synthetic materials that are inexpensive and not radioactive.


J. Sean Keane

Vaseline Glass With a Gatorade Glow

If you plan on faceting anything radioactive, I recommend you follow these safety precautions. The radioactivity and amount of uranium in uranium glass vary widely. I collect the stuff and have a plate from the 1930s that is too hot (45 millirems/hr) to ship by the PO or UPS. However, much of the material sold lately has only a fraction of a percent uranium and measures only slightly above background. I recently purchased a piece of uranium glass that doesn’t even measure a millirem/hour per gram. However, the glass is rich in lead oxide as well, so precautions do need to be taken.

“Uranium Glass” by shiu_ is licensed under CC By-SA 2.0
“Uranium Glass” by shiu_ is licensed under CC By-SA 2.0

Sometimes uranium glass is sold as “Vaseline glass” because of its color and luster. An interesting thing about uranium glass is that it fluoresces under ultraviolet light. When I put my “hot dish” under a longwave UV light, it lights up the whole room up with a “Gatorade” greenish-yellow light.

If you’re uncomfortable with the material and the safety precautions, it would probably be best to keep your piece as a curio and not cut it.

Donald Clark, CSM IMG

Geiger Counters, Chalcedony Fluorescence, And Uranium Salts

Be advised that not just “weird physicist friends” are likely to have Geiger counters. Gemologists are also likely to have them in well-equipped gem labs. Uranium glass isn’t the only material containing uranium that a gem cutter might encounter. The typically bright fluorescence of chalcedony in geodes is due to uranium salts.

Larry Meyer, Gold Country Gems

“Schroedinger's Martini” by Lenore Edman is licensed under CC By 2.0
“Schroedinger’s Martini” by Lenore Edman is licensed under CC By 2.0