Uranium glass

There are some fascinating items that come from the past. Just one of these is uranium glassware that captivates us, big and small, by glowing under UV light. So much so that collectors always carry their UV-Scorpion-tracking torches when they are out hunting for bargains.

A lovely, delicate wine glass with a diamond-cut pattern. SHOP

The excitement of finding these wonderful items takes me back to the involuntary clapping and joy I often found as a child when given an ice cream. It is also fascinating to discover how this glass was made and why. Let’s explore.

How it came about

Uranium glass has a long history, dating back to 79 AD, when a mosaic in Rome was found to contain 1% uranium. In the Middle Ages, a substance called pitchblende was mined and then used to colour glass. This uraninite is a black substance composed of various metals and oxides, rich in uranium.

In 1789, a German chemist, Martin Heinrich Klaproth, having studied pitchblende, announced his discovery of uranium.

Then came Austrian Franz Xaver Riedel, credited with manufacturing the first commercial glass between 1830 and 1848 at his Bohemian factory. He called the yellowish-green uranium glass Annagruen and the yellow Annagelb after his daughter Anna Maria.

Hopping onto the bandwagon in the 1840s, famous French companies like Baccarat and Choisy-le-Roi began making some of their exquisite pieces with uranium oxide. In the 1880s, Whitefriars Glass Company in London was one of the first companies to bring uranium glass to the mass market.

When the Second World War came about, the USA started confiscating uranium for their atomic bomb project, and it became very scarce, all but collapsing the uranium glass industry. Today, very few manufacturers still make the glass.

How is it made

Glass manufacturers have often used metallic salts in their glassware to produce interesting colours, as mentioned in my previous article on carnival glass. Uranium glass is specifically made by adding uranium oxide to molten glass.

The amount of uranium can differ from very small trace amounts to 2%. In some cases, however, the uranium content has been found to exceed 25%. Now, while this may seem high, the amount of radiation will be relatively low. If, however, the piece breaks and dust or particles are inhaled or ingested, it may have toxic effects on the kidneys. Still rather not drink or eat from these items; keep them for display purposes only.

Without UV light.

With UV light

How much is uranium glass worth?

The age-old question that deserves only one answer: As much as someone is willing to pay for it. However, some pieces are more valuable than others. Some manufacturers can charge higher prices due to intricate detailing and expert manufacturing, while others produce mass-market products.

The period of time it was made can also be a factor: antique pieces are worth more than vintage ones, as is obvious, but uranium glass is one of those items collectors love, and many pieces, old or new, may command a good price.

Vaseline vs uranium glass

Sometimes, you will find the blanket term Vaseline glass used as a synonym for uranium glass. This is not actually accurate. Vaseline glass has a yellow tinge, which is why it is also called canary glass, while the green-tinted glass is just uranium glass, sometimes clear and sometimes opaque. The Vaseline term comes from the look of petroleum jelly the glass has.

If you spot some uranium glass out there while foraging for treasures, be sure to pick it up. Most will come from before WW2, so has some provenance. Besides, it’s so much fun to show everyone how it glows!