UV Pop vs. Reflected UV light

[Fire1981]

I’ve seen this difference pointed out in several threads that marbles are being ID as UV when they are actually reflecting UV light. Here are my true UVs. Is the second group are what I think the the UV reflection trait is. Am I on track here. Is the first one a combination of both? ❤️

[Fire1981]

True UV Pop🔥

[Fire1981]

Are these the marbles that are just reflecting the UV rays🔥

[Shamrock Marbles]

6 hours ago, Fire1981 said:

Are these the marbles that are just reflecting the UV rays🔥

Ric,

True UV is invisible to the human eye.  The purple/blue you see from your light source is of the wavelength that does not cause the elements in the glass to react. Reactive components need invisible wavelengths of 400nm or shorter to fluoresce.

Uranium is not the only element to fluoresce under UV.  Selenium, Cadmium and Manganese do react to UV, but not as intensely as Uranium.

These three components are very common in modern glass. Selenium is found in yellow and orange glass. Cadmium in red glass.  Manganese is used to make purple glass.

 So, it is a misnomer to say you see glass reflecting UV. -John

[Melissa]

Great question. I’m confused on this topic as well.

[Alan]

On 1/26/2023 at 11:43 PM, Fire1981 said:

Are these the marbles that are just reflecting the UV rays🔥

Those are reflecting the UV light.

[Steph]

There are some non-uranium reactions to UV light.  Red/orange glow does occur.  I would attribute Rick's red and oranges to some non-uranium chemical such as manganese.  

But have seen people present marbles as reacting to UV, when they weren't glowing but just sort of had an interesting look to them because it was blacklight not daylight which was shining on them.  

That's what I thought was meant by reflection verses reaction.  

Sorry, I can't track down the example I was thinking of most recently -- it was someone who said that each and every one of his Jabos in some large group reacted to UV.   The photo he showed after that was just a normal Jabo distribution of glow.  Some reacting.  Most not.  But the new collector thought there was reaction in all.