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Uranium Glass (wikipedia.org)
102 points by hdivider 6 hours ago | flag | hide | past | favorite | 63 comments

I have some marbles and a crucifix ( that kind you hang on a wall) made of this material. I inherited them from my grandmother , the marbles was intended to be toys. The crucifix also is visible in the dark and it's the object with major emissions, but nothing dramatic. The marbles emit mostly alpha rays. Both can excite notably my Geiger counter, but, storing them in a metallic box, (i.e. that sheet metal box for biscuits ), no emission leaks. I'm using the marble in my DIY random number generator, based on a Geiger tube and an Arduino board.

> I'm using the marble in my DIY random number generator, based on a Geiger tube and an Arduino board.

This is so nerdish, I love it!

So the crucifix is visible in the dark? This article makes it sound like a black light needed to observe the phenomenon, which strikes me as odd because I wouldn't have thought black lights were commonly available at the time when these first gained popularity.

The crucifix is different, besides the Uranium glass it has engravings painted with something I think is tritium.

That is a little scary - a bit into the territory of https://en.wikipedia.org/wiki/Radium_Girls

Radium more likely. Tritium is produced in small quantities in nuclear reactors and is the fuel for fusion bombs. I doubt that was used to make a crucifix.

How old is it? Tritium has a half life of only 12.3 years, so if it's more than 60 years or so old, there's basically none left (around 3%), certainly not enough to make it glow.

Radium is much more likely if it's still glowing.

Do you have a link or project site for the DIY random number generator? I'd like to read about it :)

I was thinking to make it public, but it's based on an Arduino shield I purchased the day after the Fukushima accident, it is no more in commerce. I should make it more generic changing hardware. I think you can find online similar projects.

Maybe your grandmother purchased them from Bob Lazar: https://unitednuclear.com/index.php?main_page=product_info&c...

No, the color isn't the same. This is their color: https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.worthp...


Couldn't you just measure background radiation?

My device, as other implementation, use the particle passing through the Geiger tube as a "virtual coin" , given a sampling frequency, if one or more particles are detected the firmware returns 1, if no particle is detected, zero. In other words, the random numbers are built a bit at time. My configuration with the background radiation returns too many zeros, so I needed something more ... lively. Anyway, what is the point to use the natural radiation if you have the serious stuff ? :-) When I say that the device is a nuclear RNG, peoples smile but when I turn it on and they listen the characteristic sound of a Geiger counter, the average reaction is "WHAAAAAATTTT ????". It's funny.

John Von Neumann’s method of creating a uniform distribution of random numbers from a skewed source (too many zeros) was:

“(From a stream of) bits, (take) two at a time (first and second, then third and fourth, and so on). If the two bits matched, no output was generated. If the bits differed, the value of the first bit was output … (this) can be shown to produce a uniform output even if the distribution of input bits is not uniform so long as each bit has the same probability of being one and there is no correlation between successive bits.” (Edited from Wikipedia)

I have serious concerns about purchasing one and being put on "a list".

But this city is lackadaisical at best when it comes to industry. And we've had incidents where radioactive materials have been found in construction near homes.

So IDK. I feel like I probably should have one.

You don't have to look very hard to find entropy, but finding it in a cool and fun way is rare. This is way higher on both the functionality and fun scales than a wall of lava lamps.

Would that be cryptographically secure? Couldn't someone perturb an RNG based on background radiation by beaming radiation at it?

That argument relies on independent samples, but if someone's beaming radiation at the device to control its output, the samples will not be independent.

One of my favorite YouTube channles, Nile Red, has a cool video showing how to make Uranium Glass:


He also posted a video about cleaning up on NileBlue. I appreciate the effort that goes into documenting this process - for anyone interested in working with chemicals, waste disposal is extremely important.


Ads every 2 minutes, host has zero personality and seems to have no real understanding of the safety issues he's dealing with. Not for me...

I think this is a very mean commentary. I usually don't feel the urge to comment, but this is a really mean commentary

I'd much prefer a slightly dry but genuine personality, than a hyperactive and fake "youtuber personality". The content speaks for itself. He generally takes safety pretty seriously, too.

YouTube premium removes ads. If you watch an hour or more of his videos you’ll realize he’s an extremely cautious creator and knows what he’s doing.

>> Ads every 2 minutes

> YouTube premium removes ads

Ads every 2 minutes won't make me give Google money, at best they'd drive me away from the site. As a matter of fact, last time i tried to watch a long video it did have ads every 2 min. Fortunately it was a speedrun of a game so I just found a similar one on Twitch.

There have been quite a few photographic lenses containing radioisotopes: https://camerapedia.fandom.com/wiki/Radioactive_lenses

A few years ago I sent an Olympus Zuiko 55mm 1.2 to a friend in Russia. It has thorium in its glass elements. The lens didn't arrive for weeks and he started worrying whether it was lost on the way. He then was summoned by the customs authority to make a statement on the radioactive material he was importing. Turns out, during import they take a radioactivity reading on a container full of packages. This lens alone was radioactive enough to trigger the alarm for the container, and they had to make multiple readings (like in the puzzle with the coins of different weight) to find the radioactive package.

In the end, I think he had to give up the lens.

I thought this might have been an article on turning nuclear waste into glass (vitrification). Might be of interest to some people especially given current questions/challenges regarding reclassifying nuclear as "renewable":


Nuclear is “clean” energy in terms of generating minimal waste compared with natural gas, coal, hydro etc. It’s not technically renewable but it’s widely available enough to the point that it could power our civilization for a good long while. Enough time that fusion should become feasible which technically isn’t renewable either since there’s a finite amount of hydrogen in the world but should be enough to see us through building a Dyson sphere of some kind.

After buying a MightyOhm geiger counter kit[0], I needed something to test it with. Uranium glass ended up being one of the cheapest things you can buy that will register above the background radiation level.

[0]: https://mightyohm.com/blog/products/geiger-counter/

Related: Fiesta Ware. Maybe worth going through the thrift store with a Geiger counter.


Looking around ebay for a geiger counter and found this post, which includes some pieces of Fiesta Ware as a test source.


For a rather wide variety of uranium glass objects: https://attic.city/search/usa/Uranium

FYI, Attic is our niche search engine for goods from small, independent businesses. You’re not gonna find much Uranium glass from the likes of Home Depot, Amazon or Walmart :)

Turns out the UV-A from black lights in not entirely safe. Can cause wrinkles and skin cancer log term as well as short and long term damage to eyes. I'm glad I haven't used mine since college.

I don't see anything that indicates that this could be dangerous, so I have to assume that it is safe.

I do know that pigments made from uranium oxide (bright white), in cloisonné, can be quite dangerous.

Of course, radium pigments were very dangerous (not to mention the medicinal philters).

Most of it is safe to have in a display case. I have an antique uranium glass photo filter that's hot enough that I keep it in a metal box. All of the pieces I have put out enough beta radiation to easily detect. I don't have an alpha counter.

You wouldn't want to grind it up and inhale the dust. I winced when I saw someone on Etsy selling uranium glass shards they'd tried to reclaim from broken pieces by putting them in a rock tumbler to make them look like beach glass.

I wouldn't recommend actually eating off of it either, but most of it is so old and fragile you'd probably want to avoid that anyway.

And I don't see any indication of this being safe :)

It's radiation isn't it? Most of the stuff I encounter on a daily basis are much lower on the table. So there must be some differences.

These things aren't dangerous unless you grind them to dust and snort them. You're being blasted by space and earth radiation every single second of your life, the level of radiation emitted by these items isn't enough to be a problem

Light is radiation. There is no reason to be scared without understanding

Fun to see on HN. Just in the last couple weeks I purchased a UV flashlight to search for this glass.

Interesting. The uranium is stable, right?

The radioactivity is minimal. BUT - if you break the glass or scrape it (for example with cutlery while eating) you can release shards and/or dust which may contain alpha emitters.

Ingesting those is a bad idea, even if the glass is a very weak source.

Side note: turns out that mid-century Fiesta Ware was made with uranium glazes (nice colours...) and it's definitely not 100% safe if broken or chipped.

Even if you ignore the radioactivity, uranium is quite a toxic element in its own right. Glass should be chemically stable under normal use, but glazes definitely aren't.

> if you break the glass

Isn't this the ultimate fate of all glass?

Stable compared to U-235? Yes. Stable compared to Carbon 13? No.

Uranium has no stable isotopes, although natural isotopes have a half life of billions of years.

Maybe nothing is stable, not even protons[0].

[0] https://en.wikipedia.org/wiki/Proton_decay

No its uranium.

Is this glass dangerous then?

> ... can register above background radiation on a sufficiently sensitive Geiger counter, although most pieces of uranium glass are considered to be harmless and only negligibly radioactive.

Missed that. Thanks.

Uranium, like lead, mercury, cadmium, arsenic, is a heavy metal and toxic, separate from any radiation, although the alpha particles from U-238 are only dangerous if ingested or inhaled, anyway.

The food you eat every day is much more dangerous than Uranium glass, unless you also eat Uranium glass.

It's U-238, so the half-life is about 4.6 Billion years. Not totally stable, but pretty damn stable.

I don't think stable refers to the half life. It's a binary status.

Good point; it would be interesting to calculate how many atoms per second disintegrate in, say, one gram of the "relatively stable" U-238 - my guess is, quite a few!

If I remember this correctly...

²³⁸U has an atomic mass of 238.05078826, so one mole of ²³⁸U weighs 238.05078826g. One mole means the Avagadro number of atoms, 6.02214076×10²³.

Diving by 238.05078826 gives 1g of ²³⁸U having 2.52977×10²¹ atoms.

²³⁸U's half life of 4.468 billion years is 1.4099635×10¹⁷ seconds, so in 1 second

will decay. Double precision arithmetic isn't enough for this (though it is for 1 day), but Wolfram's calculator works: 12,436 atoms decay.


That's true, sort of. Some elements can have such long half lives they are effectively stable, and can be treated as if they are. For example tellurium 123, 128, and 130; and Bismuth 209.

Oh, is that where the iconic radioactive green color comes from?

No, that is more from the association of radioactivity with radium paint, which is a mixture of radium and a phosphor, similar to glow-in-the-dark paint. The radium will keep the phosphor "charged" so that the paint will keep glowing without having to be exposed to a light source.

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