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How to Test Vaseline Glass

"Vaseline glass" is a term used in the United States to identify a transparent yellow-green glass produced from the 1830s through today, which enjoyed its greatest popularity from about 1880 to 1920. Its color derives from the addition of a uranium salt called uranium dioxide to the glass mixture. Today, the expense and regulation of substances containing uranium limits production of this glass. The uranium in Vaseline glass fluoresces when exposed to ultraviolet light, and produces enough radiation to activate a Geiger counter.

Things You'll Need

Ultraviolet light
Geiger counter

Instructions

- 1
  Examine the glassware first under incandescent light, and then in outdoor sunlight (if possible). The item should look more yellow than yellow-green under incandescent light, and more yellow-green in outdoor sunlight.
- 2
  Examine the glassware under ultraviolet light --- preferably in a darkened room --- by using a black light. Vaseline glass fluoresces with a bright neon-green color, the intensity of which varies depending on the exact mix of ingredients. This is the easiest method of testing Vaseline glass; however, not all glass that glows is Vaseline glass. According to "Collector's Weekly," Burmese glass and Custard glass also glow, but under normal light they are opaque rather than transparent.
- 3
  Use a Geiger counter to test the glassware for radioactivity. Although the level of radioactivity in Vaseline glass is too low to harm a person during normal use, it is strong enough to detect using a Geiger counter.

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