What is Vaseline Glass?

Also known as uranium glass, Vaseline glass has had uranium, usually in oxide diuranate or depleted uranium form, added to the glass mixture before melting it. The proportions of uranium added is small, usually trace amounts to no more than 2%. However, in the 1800's as much as 25% uranium was added to the glass mixture.Vaseline glass was once popular and made into household items and tableware, though during the Cold War uranium was hard for many factories to obtain. This antique glassware is now considered to be a collectible by some, though others see it as mainly a novelty. Present day uranium glass is found only in small objects such as marbles or beads.

The normal color of Vaseline glass ranging from green to yellow is dependent on the amount of oxidation and concentration of metal ions, although it is sometimes altered by the addition of glass colorants. Under ultraviolet light true uranium glass looks bright green. Although considered harmless and only slightly radioactive, it can register as radioactive on a sufficiently sensitive Geiger counter.In the 1920's uranium glass received the nickname "Vaseline glass" because the typical color is a pale yellowish-green, much like the petroleum jelly marketed at that time.

Vaseline glass is many times used to describe any uranium glass, regardless of the color. Many times the nickname is also applied to other types of glass that appear to be uranium glass because of their appearance in normal light, although they don't fluoresce green when under black light. This is the only true way to tell whether or not the glassware in question is actually uranium glass since even the most trained eye can be fooled by a lookalike.

There are many other common subtypes of uranium glass with their own nicknames such as "jadeite glass" which is semi-opaque or opaque green, "custard glass" which is semi-opaque pale yellow, and "Depression glass" which is a transparent or semitransparent pale green. Much like Vaseline glass, the terms jadeite glass and custard glass are often used solely because of the glassware's appearance and not the fact of whether or not it contains uranium. Also, Depression glass is used as a general description for any glassware manufactured during the Great Depression regardless of its formula or appearance.

Uranium glass has been in use as far back as 79 AD when a mosaic containing a yellow glass was found to have 1% uranium oxide added. R.T. Gunther discovered the mosaic in a Roman villa in the Bay of Naples, Italy back in 1912. In the mid 19th century uranium glass was mass-produced and become widely popular in both the United States and Europe.