Vaseline glass

How to read it

ORAU’s Museum of Radiation and Radioactivity defines Vaseline glass as transparent yellow to yellow-green glass that owes its color to uranium, often about 2 percent by weight. The name, after the petroleum jelly, is a collectors’ name, and the sources date it differently: ORAU says it probably dates from the 1950s, while the Maryland Archaeological Conservation Lab says it has been in common use since the 1930s. The makers had their own names. Canary glass is the older one, first used in the 1840s according to ORAU, and the National Heisey Glass Museum says Heisey called the color Canary where collectors say Vaseline. The EPA uses both as nicknames for the same yellow uranium glass.

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Vaseline glass or uranium glass?

All Vaseline glass is uranium glass, but not all uranium glass is Vaseline glass. ORAU warns that using the two names as synonyms causes confusion, because uranium also colors opaque glass, such as custard glass and Burmese glass, and Vaseline glass is transparent. Collectors also argue about green. ORAU notes that purists would not count a green piece colored with iron as well as uranium as Vaseline glass, and might call it Depression glass instead. Michigan State University’s Campus Archaeology Program says iron oxide was added during the Depression to make the glow greener, and that some collectors don’t count those pieces as true uranium glass.

Look-alikes

Some transparent yellow or yellow-green glass is colored with other additives, such as cerium oxide, and ORAU says it can look exactly like Vaseline glass; it may even be slightly radioactive from thorium impurities. ORAU’s test is a black light in the dark: glass that glows a rich green contains uranium. That glow is also why, ORAU says, a piece that looks yellow indoors under incandescent light can look greenish outdoors.

Heisey’s Canary

Heisey made Canary early on, so known pieces are in its earlier patterns: #150 Pointed Oval in Diamond Point, #1280 Winged Scroll and #160 Locket on Chain. The National Heisey Glass Museum says these tend to be bright yellow. Heisey reissued the color in a limited supply after 1922, in patterns such as #465 Recessed Panel, #351 Priscilla and #1184 Yeoman, mostly in accessories such as vases and compotes, and the later Canary tends to be paler.

Before and after the war

ORAU says uranium colored glass from the 1830s on, apart from a gap of fifteen years or so beginning in the Second World War. Natural uranium was used before the war; when Vaseline glass production resumed in 1959, makers switched to depleted uranium. In 2004 ORAU listed four US companies still making it, all decorative: Boyd Crystal Art Glass, Mosser, Summit Glass and Fenton.