Yes, uranium is radioactive and that word scares people but the kind of uranium used in tinting glass is safe to handle. It gives off very low level alpha rays (these rays can not penetrate skin so they are not dangerous to touch) and in rare cases some will omit very low level gamma radiation (still well below safe handling levels).
With that said we do recommend you do not use these items for food, mainly because uranium is also toxic when ingested and it can leach into your food (especially when using acidic liquids like tomato juice) and also if a chip of it was to break off and ingested it could do harm internally (most cases your body would just pass it on and out but a chance exists that it would be lodged inside and that would be bad over time) so please do not use it for food just display.
Natural occurring uranium salts are very stable and it slowly breaks down over millions of years… The uranium used in weapons and nuclear plants is purposely modified in a way that it becomes unstable (making it highly radioactive – known as weaponized uranium or uranium used in power plants that gives off extreme heat).
Why collect it? Well its old, very pretty and a great conversation piece just to name a few reasons (we love it and we too are collectors of uranium art glass). The most interesting reason for most people is the way it reacts to BlackLight (Purple UV light) – it glows (turns bright green) when in the presence of UV! (see image) we give our customers a free keychain blacklight with any uranium glass item and give them two safe handling instructions.
- Do not use it for food
- Wash hands after handling it (incase of chips) cause you do not want to get a piece in your mouth no matter how small it is.
Will it register on a geiger counter? Yes, It will also register on a gieger counter at very low levels but it is much easier to grab a key chain sized blacklight flashlight so you can test these items on the road or impress your friends!
We do have a dosimeter (personal geiger counter) in the store if you would like to know how much radiation your piece emits or would like us to show you in person. In most cases the levels are about 3 times higher then normal background radiation but you have to place the geiger counter on the glass to get any reading at all as the levels are so low. We have found a few pieces that are 8 times higher but that is a rare item (and still safe to handle).
Are other antiques radioactive? Yes, Other items such as thorium mantles (for lanterns) and radium painted clocks (glow n the dark dials) are also radioactive and radium as well as thorium can be unsafe to handle for long periods of time as these radioactive elements are more unstable and release gamma radiation that can penetrate skin but the levels are still very low and it would take a fairly long time (years) of close exposure to increase any risk to you. These types of items need to be kept at least a foot or two away from anyplace where someone may sit or stand or long periods of time. Also noted Some clay pottery also has trace elements that can omit radiation (such as red fiestaware and some english and chinese pottery). These items are still all safe if handled with care and knowledge and not used for food usage.
Whats it worth? A single Uranium filled marble pre 1940 can be worth 10+ dollars – we have a rather unique BLUE marble at the store that lights up bright green when exposed to UV light! This would sell for about 80.00 due to its rarity (i bet i checked 10000 marbles before I found one).
Some uranium glass items are worth 1000’s but on average most common items sell for less then 150.00 and many under 30.00
What makes it glow?
It is indeed the Uranium content in the glass that makes it glow green. Uranium salts (Uranium Dioxide) are added to a glass mix (at the time of melting). The proportion usually varies from trace levels to 25% uranium depending on how rich of color the glass maker was after.
When was it made? Uranium glass was first made about 89AD but most that we see today was made between 1850 and 1940. Up until about the mid 1930’s it was made into tableware and household items but fell out of widespread use when the availability of uranium to most industries was sharply curtailed during the Cold War. Some companies still use it today for specialty glass and pottery glazes but the really collectible stuff is the depression era items.
Why was it used? Uranium salts are a vivid yellow color and is why they were chosen to tint glass yellow and green. No one knew what radiation was at the time either… They just knew that if added to the glass mixture a great green color was produced.
What exactly is “Vaseline Glass”?
Vaseline glass is pale yellowish-green uranium glass that looks like vaseline which in the 1920s led to the nickname vaseline glass (based on a resemblance of petroleum jelly as formulated and commercially sold at that time). Specialized collectors still define “vaseline glass” as transparent or semitransparent uranium glass in this specific colour. “Vaseline glass” is now frequently used as a synonym for any uranium glass, especially in the United States, but this usage is not universal. The term is sometimes carelessly applied to other types of glass based on certain aspects of their superficial appearance in normal light, regardless of actual uranium content which requires a blacklight test to verify the characteristic green fluorescence.
About the photos…
As you can see we love this stuff. We have a full cabinet at the store with it. We found a great heart shaped trinket box and it glows really nice under blacklight. We have some candle sticks, a spittoon, salt & peppers, dishes, dessert glasses, shot glasses, Platters and Much more. Come on in to see the really neat blue marble that turns green when exposed to the purple light (Neat parlor trick)