Uranium was first used to color glass in the 1830s and it has continued to be used for this purpose with the exception of a fifteen year (or so) period beginning in World War II. Some uranium-containing glass does not fluoresce under ultraviolet light, e.g., the yellow glass 'gemstone' does not fluoresce under UV despite the fact that it contains uranium!Īn analysis indicates that all the pictured items contain natural uranium except the tube on the right which contains depleted uranium. This green fluorescence explains why an example of Vaseline glass that looks yellow under incandescent lighting might take on a greenish tinge when viewed outdoors. If the glass glows a rich green color, it contains uranium. Perhaps the most reliable way to identify the presence of uranium in the glass is to expose it in the dark to a source of ultraviolet light (e.g., a black light). To confuse matters somewhat, this non-Vaseline glass might even be radioactive due to the presence of thorium impurities! Some transparent yellow or yellow-green glass has been colored using additives other than uranium (e.g., cerium oxide), and it can look exactly like Vaseline glass. Canary glass is an even older name that was first used in the 1840s to describe what is now referred to as Vaseline glass. Uranium glass, an older and more general term, is sometimes used as a synonym for Vaseline glass, but this can lead to confusion because some types of glass colored with uranium (e.g., custard glass and Burmese glass) are opaque whereas Vaseline glass is transparent.

Vaseline glass is a recent term that probably dates from the 1950s. These cognoscenti might describe it as “Depression Glass,” a less desirable commodity. Purists might argue that the green sugar bowl in the picture should not be considered Vaseline glass because an additional colorant (probably iron) has been used in addition to the uranium to produce the green. Vaseline glass, like the candlestick holder shown here, is a term for the transparent yellow to yellow-green glass that owes its color to its uranium content.

Portable black light for uranium glass