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Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?

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chopin-liszt:
The fluoresence arises from the radioactive component of the metal.
There are three isotopes of uranium, U-234, U-235 and U-238. Only the latter two are radioactive, and neither is terribly strong, they are just alpha emitters. A weak source, easily stopped with a sheet of paper. Only harmful if ingested.
(This is a very simplistic explanation. Other isotopes can be created and we are not talking about depleted uranium which is the really dangerous stuff.)

You might be aware that lead lined boxes are what radioactive stuff is kept in? Lead stops even stronger activity than Uranium.
I imagine lead in the glass might have the same shielding effect.

Anne and me cross-posting.  :-*

flying free:
Thank you both :)

So if it turns out to be correct that lead stops uranium fluorescing then for the sake of debate I might reasonably assume that the V&A QV bowl was probably made with unleaded glass.  Which means if it was made here it in 1837 it would have been made by a maker using non lead crystal in the batch.  I wonder did they routinely make up both a leaded crystal for clear cut glass and a non leaded batch for particular reasons to do with colour?

Or did they just add uranium to the lead batches, to create a colour. They wouldn't have known about the fluorescence at that time would they?
See John Ford recipe here:
https://www.glassmessages.com/index.php/topic,70066.msg403520.html#msg403520

chopin-liszt:
The weakly radioactive alpha particles have enough energy to shift the wavelength of light you are using,(uv) into the wavelength of the glow (green) you see.
That is what radioactive fluoresence is.
Fluoresence is not a property of uranium, per se.
The lead will block the particles from progressing, but they do not stop what the uranium is doing itself.
(I'm being pedantic about you saying the lead stops it from fluorescing, m, 'cos it doesn't, not really.)
Fluoresence is the shifting of the light from one (dullish) wavelength to the brighter one.
It sort of happens inbetween the item, the light source and your eyes.

There are other non-radioactive chemicals which are fluorescent. eg fluorescene.

flying free:
ok, I vaguely follow that Sue :)  Thanks for taking the time to explain.

I think the article in Pressglas-korrespondenz was trying to make a point though about using uranium oxide in lead glass.
Was it perhaps about making an opalescent or opaline effect with uranium and that in lead glass the lead stopped that effect happening maybe?   The article appears to indicate that there was no interest in using uranium oxide in lead crystal batches but did it mean only in the instance of opaline/opalescent effect.  Could it be that the opalescent or opaline effect didn't happen in lead glass thereby indicating that opalescent uranium glass or opaline uranium glass is only found in Bohemian non lead glass.

It's trying to make a point but I don't know which point :)  I suppose it could be the explanation as to why there may be no opaline/opalescent uranium glass French opalines (lead glass) but only Bohemian ones (non-lead glass)?  I don't know if that's true btw but I don't recall seeing any (not that my list of viewing is exhaustive at all though).

John Ford seemed apparently happy with his uranium oxide in lead glass outcome. 

glassobsessed:
Lead was added to give the resulting glass good clarity, surely counter productive if you want an opaline. A byproduct of adding lead is that it makes the glass softer so it is easier to cut, not certain about this but it may make it less brittle too.

John

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