Yellow Uranium Glass Ball
In the past, glass manufacturers added uranium to glass for color. Uranium has since become more strictly regulated, but the old uranium glass objects are still floating around. Because of the uranium content, these marbles glow bright green under ultraviolet light.
- Size is around ⅞ – 1” diameter.
- Some dents and manufacturing imperfections can be expected.
- Slightly radioactive, but they're harmless.
- Makes a great sample for uranium if you're collecting the elements
This item pairs well with our ultraviolet LED flashlights.
Uranium glass is glass which has had uranium, usually in oxide diuranate form, added to a glass mix before melting for coloration. The proportion usually varies from trace levels to about 2% uranium by weight, although some 20th-century pieces were made with up to 25% uranium.
Uranium glass was once made into tableware and household items, but fell out of widespread use when the availability of uranium to most industries was sharply curtailed during the Cold War in the 1940s to 1990s. Most such objects are now considered antiques or retro-era collectibles, although there has been a minor revival in art glassware. Otherwise, modern uranium glass is now mainly limited to small objects like beads or marbles as scientific or decorative novelties.
The normal color of uranium glass ranges from yellow to green depending on the oxidation state and concentration of the metal ions, although this may be altered by the addition of other elements as glass colorants. Uranium glass also fluoresces bright green under ultraviolet light and can register above background radiation on a sufficiently sensitive Geiger counter, although most pieces of uranium glass are considered to be harmless and only negligibly radioactive.
The most typical color of uranium glass is pale yellowish-green, which in the 1930s led to the nickname Vaseline glass based on a perceived resemblance to the appearance (which was a yellow-green color) of Vaseline brand petroleum jelly as formulated and commercially sold at that time. Specialized collectors still define Vaseline glass as transparent or semi-transparent uranium glass in this specific color.
Vaseline glass is sometimes used as a synonym for any uranium glass, especially in the United States, but this usage is frowned on, since Vaseline brand petroleum jelly was only yellow, not other colors. The term is sometimes carelessly applied to other types of glass based on certain aspects of their superficial appearance in normal light, regardless of actual uranium content which requires a blacklight test to verify the characteristic green fluorescence.
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable; the half-lives of its naturally occurring isotopes range between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.
In nature, uranium is found as uranium-238 (99.2739–99.2752%), uranium-235 (0.7198–0.7202%), and a very small amount of uranium-234 (0.0050–0.0059%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years, making them useful in dating the age of the Earth.
I'm building a tiny cave in my curio cabinet for all my UV reactive specimens, and these marbles really pop under the blacklight.