Glow under Black Light

[lostafewofem]

I've read about vaseline glass, which glows bright yellow to yellow/green under a black light.  I believe it may have some uranium or some other element which causes the glow.  Please correct me and educate me on that if I am wrong.  But, I've also discovered at several of the marbles in my find which glow orange/red under black light.  What causes that?  There is at least one which appears a very dark translucent (green black) with light colored swirls internally (to the naked eye), then under black light, there is the orange/red glow imbedded.  Fascinating.  What's this?  Anyone?

[Steph]

Yes to uranium for the bright yellow and yellow/green.

(I think something else may cause some shades of green, but yes to uranium being the typical cause of that.)

 

I think it is manganese which usually gives us the orange and red glow.  (It's an m-word but I often forget which one.  I think I have it correct this time.)

 

If you pull the brightest glowing marbles out and let your eyes get adjusted to the dark again, other marbles will then seem to come through relatively brightly.  If you do that a few times, you can get down to levels of glow with different colors coming through.  But they're more subtle.  I don't know what causes all the different shades.  It's just fun to notice sometimes. 

[JerryG]

16 minutes ago, Steph said:

I think it is manganese which usually gives us the orange and red glow.  (It's an m-word but I often forget which one.  I think I have it correct this time.)

Yes. Manganese or Magnesium. 

[J_Ding]

Yes.  The first one you mentioned Jerry, manganese or Mn for short, is that one that gives oranges and reds.  John

[lostafewofem]

Cool!  Thanks, all

 

[ManofKent]

Interesting. Was Thorium ever used in marble production? I've got old camera lenses from the 1960's which are slightly radioactive and now quite deep yellow in colour.

[Steph]

Never heard of it.  While other people are thinking about it, I sent a question off to a friend who might know.  

[ManofKent]

24 minutes ago, Steph said:

Never heard of it.  While other people are thinking about it, I sent a question off to a friend who might know.  

It's highly refractive and was used in camera lenses to reduce chromatic aberration (colour separation). It turns glass brownish/yellow after a while but if left exposed to a strong UV source will revert to clear. Like lead it makes glass appear brighter and clearer, and wondered whether it was used in marble production.

[ann]

I've gone over a fairly large number of glass formulas from Akro Agate and don't remember ever seeing it in any, but I'll check.  But also my source only goes up to the1930s for marbles.

[Steph]

So, my source is a marble maker and says he never heard of Thorium being used but once read in an article on a company overseas that at been experimenting with  it as a possible replacement for uranium.  He expects it's possible for some of the glass by-product into a marble maker's hands.  

Also, he noted that there might be some issues with the radioactivity of the Thorium ... so don't put it up to your eyes unless you're sure it's okay!

 

So, Richard, to add a little background and to put it together with what I learned just now:   Marblemakers do a lot of glass recycling.  They don't mix up all their glass from scratch with a formula anymore.  The recycled glass from other sources could have included Thorium.  My marble-making friend is not aware of it being done on a systematic basis.  

[ManofKent]

4 hours ago, Steph said:

So, my source is a marble maker and says he never heard of Thorium being used but once read in an article on a company overseas that at been experimenting with  it as a possible replacement for uranium.  He expects it's possible for some of the glass by-product into a marble maker's hands.  

Also, he noted that there might be some issues with the radioactivity of the Thorium ... so don't put it up to your eyes unless you're sure it's okay!

 

So, Richard, to add a little background and to put it together with what I learned just now:   Marblemakers do a lot of glass recycling.  They don't mix up all their glass from scratch with a formula anymore.  The recycled glass from other sources could have included Thorium.  My marble-making friend is not aware of it being done on a systematic basis.  

Thanks both. I know a fair bit about optical glass, but as you'll have realised not a lot about marble glass! I find it amazing how casually heavy metals were used in glass making.

[ann]

Yup.  That's why a few of the old marble-making sites -- where they did mix their own formulas -- have wound up as Superfund sites today.  Buncha stuff in the ground . . .