Uranium glass, also known as Vaseline glass, is a type of glass that contains a small amount of uranium oxide, typically between 0.1% and 2%. This gives the glass a distinct yellowish-green color and, more notably, causes it to fluoresce a bright green under ultraviolet (UV) light. Uranium glass has been produced since the early 19th century and is often sought after by collectors.
Characteristics of Uranium Glass:
- Color: Uranium glass often has a pale yellow-green color, although it can also appear in other shades such as clear, white, or a range of pastel colors.
- Fluorescence: When exposed to UV light (also known as black light), uranium glass fluoresces a bright green color. This is due to the presence of uranium oxide in the glass.
- Radioactivity: Uranium glass is mildly radioactive due to the uranium content, but the levels are generally considered safe for handling and display.
- Historical Use: Uranium glass has been used to make a variety of decorative and functional items such as bowls, glasses, vases, and ornaments.
Identification Techniques:
- Visual Inspection: Look for the distinctive yellowish-green color, which can vary in intensity. Uranium glass can also be found in other colors due to added pigments.
- UV Light Test: Use a UV light to check for fluorescence. Uranium glass will glow a bright green color under UV light, which is one of its most notable characteristics.
- Geiger Counter Test: Since uranium glass is mildly radioactive, a Geiger counter can be used to detect its radioactivity. However, the levels are usually very low and considered safe.
- Examine Markings: Look for manufacturer’s marks or labels that might indicate the origin or production period of the glass. Certain makers and periods are known for producing uranium glass.
- Check the Age: Uranium glass production was most popular during the late 19th and early 20th centuries, although it has been produced in smaller quantities in more recent times.
Safety Considerations:
- Handling: Uranium glass is considered safe for handling, but prolonged exposure, especially to certain high-radioactivity pieces, should be minimized.
- Storage: Store uranium glass away from children and pregnant women to minimize any potential risks, although the risk is generally very low.
Uranium glass can be a beautiful and fascinating addition to a collection. By using the identification techniques above, you can better determine whether a piece of glass contains uranium and appreciate its unique qualities.