Uranium Glass Ball (Imperfect)

Uranium glass is made with a small amount of uranium, the element with atomic number 92. Glassmakers added uranium compounds to create vibrant yellow and green colors, but the uranium also gives the glass an unexpected property: under ultraviolet light, it fluoresces with an intense neon-green glow.

The glass became especially popular during the Victorian era, when uranium glass was prized for its striking colors. At the time, few people ever saw it because UV lights were not readily available. Production declined during the mid-20th century as uranium became more tightly regulated. Today, inexpensive UV flashlights have given uranium glass a resurgence in popularity.

The presence of uranium also means the glass is radioactive—although weakly. For reference, sitting in a bathtub filled with typical uranium glass is comparable in radiation exposure to sitting on an airline flight. Harmless enough to handle but avoid eating it.

• 1” diameter.
• These are being sold as imperfect and as-is. Expect cracks, chips, and manufacturing imperfections.
• A little bit radioactive, but harmless. (We measured ~0.14 μSv/h for a single ball, slightly above background radiation.)
• Glows bright green under UV light (blacklight)!
• Makes a great uranium sample if you're collecting the elements.
  

Learn more about the science behind the glow of uranium glass, and many other interesting colors, in our new book The Universe in 100 Colors.

Legality: In the US, uranium is federally regulated; however, an exception has been made for glassware containing uranium. Check your local laws if you live outside of the US.