Uranium glass (often called vaseline glass) is a unique type of collectible glassware that contains radioactive uranium oxide as a coloring agent. It was mass-produced from the 1830s until the onset of WWII.Here is the complete breakdown of what it is, how it works, and its safety:1. The Science of the GlowThe most iconic feature of uranium glass is its vibrant neon green fluorescence under ultraviolet (UV) light.
The Mechanism: This isn't caused by radioactivity itself, but by the chemistry of the uranium ions. When UV light hits the glass, it excites the electrons in the uranium, which then release energy as visible green light as they settle back down.
Identification: Collectors use a 395nm UV flashlight to identify it. If it glows bright green under 395nm, it's likely uranium. If it only glows under 365nm (a more sensitive light), it might be manganese, which is a common "false positive."
- Common Types & Names
Vaseline Glass: A subset of uranium glass that is transparent and yellow-green, resembling the color of petroleum jelly (Vaseline) from the early 20th century.
Custard Glass: Opaque, creamy-yellow glass that contains uranium.
Burmese Glass: An opaque glass that shades from pink to yellow.
Depression Glass: While not all Depression-era glass contains uranium, many green pieces from this era (1920s–30s) do.
- Safety and Radioactivity
Because it contains uranium, these pieces are radioactive, but they are generally considered safe for display.
Radiation Levels: A typical piece emits very low levels of radiation—often less than what you’d receive from a smoke detector or a cross-country flight. The glass itself blocks most of the alpha particles.
The Golden Rule: Experts and regulatory bodies (like the NRC) advise against eating or drinking from uranium glass. While the radiation is low, there is a small risk of ingesting microscopic glass flakes or uranium leaching into acidic liquids (like orange juice or wine).
Storage: It is perfectly safe to keep on a shelf. A large collection might slightly raise background radiation in a small room, but not to dangerous levels.
- History: Why did they stop making it?
Origin: Commercial production began in the 1830s in Bohemia (by Josef Riedel) and spread to the UK and USA (Fenton, Mosser, etc.).
The War Halt: In 1942, the US government seized all uranium supplies for the Manhattan Project (atomic bomb research), effectively killing the industry.
Modern Era: Production resumed in 1958 using depleted uranium, but it never regained its former popularity due to the high cost of the material and stricter regulations.
- Why do people collect it?
Today, it is a massive hobby driven by "glow hunters." Pieces can range from $5 for a simple marble to thousands of dollars for rare Victorian bride's bowls or Art Deco vanity sets.
