Topic: Bagley UV Glow

[meegs]

Mod: This post was split out of a topic in the Cafe forum as it raises a specific issue about "glass that glows".

An experienced eye can tell alot of UV glass, the realy bright stuff but not always some of the dimmer stuff. I'm sure Bagley Equinox arnt UV reactive..

Sorry I'm heading off the original topic here but I have a green Bagley equinox vase that glows, however the intensity of the glow is less than my other Bagley uranium glass. In daylight the equinox vase and the other uranium glass are more spearmint than the non uranium glass. Is there another additive to glass that could cause a glow the same colour as uranium but less intense or was there less uranium in the batch of glass that my equinox was pressed from?

Is this what you are referring to as dimmer stuff?

Cheers
Meegs

[shugdens]

Mod: This post was split out of a topic in the Cafe forum as it raises a specific issue about "glass that glows".

Sorry I'm heading off the original topic here but I have a green Bagley equinox vase that glows, however the intensity of the glow is less than my other Bagley uranium glass. In daylight the equinox vase and the other uranium glass are more spearmint than the non uranium glass. Is there another additive to glass that could cause a glow the same colour as uranium but less intense or was there less uranium in the batch of glass that my equinox was pressed from?

Is this what you are referring to as dimmer stuff?

Cheers
Meegs

Have you got the frosted type of green or the clear type of green? I've had quite a few of both say 3/4 and never had one glow. Maybe they just dont glow a lot. I used to have a full uv strip light from my raving days that would give a dim glow off most green glass, it would even get a blue glow off some blues.

Onr of the experts could fill us in here??

[Angela B]

There are some Bagley glass pieces that glow and others that don't. Quote from my newly published book on Bagley Glass (on page 14):

About two years after the war ended, around 1946, the government confiscated Bagley's stocks of uranium-enriched glass ingredients (several tons). Bagley glass made after this date does not contain uranium so does not fluoresce under ultra-violet light, a useful test for age of Bagley's green and yellow glass.

The Equinox bowl was made from 1938 to 1975 with a gap during the war (1940 to 1945), so those early pieces from the first years will glow, later ones are unlikely to glow.

The green colour in Bagley glass varies quite a lot, from a rather blue shade (presumably what you have called "spearmint" -what a good name) to a yellowy green. No-one has ever explained this difference to me, other than variations in the glass ingredients. I don't think it is a date thing, as all the shades of green sometimes contain uranium and sometimes do not.
Hope this helps.
Angela

[Lustrousstone]

Bagley green is generally probably what you would describe as spearmint whether it contains uranium or not, i.e., with a hint of blue IMHO.

Less uranium doesn't mean a dimmer glow; it seems to mean a glow of the same intensity and shade of green but less concentrated (if that makes sense). Sometimes the glow is slightly reduced by other colorants but generally a UV LED light will make uranium glow from several feet away.

I have yet to personally find an Equinox that contains uranium and I've been looking for uranium stuff for at least six years. I know they exist though because I've seen them glowing online.

I don't have a piece of non-uranium Bagley on hand to test but I suspect your dim Equinox contains manganese decoloriser. That too glows green under UV but the effect is dimmer, more yellow and more diffuse. It's a different physicochemical reaction. Try your UV light on a different colour of Bagley or on some old clear glass and you may see what I mean. This effect does vary with manganese concentration from yellowish green to very green and generally you have to hold your light source close to see it.

If your post a picture of your bowl in daylight I could hazard a guess at whether it contains uranium.

[meegs]

Hi Everybody,
As it is now dark here I've dragged the UV light out and while I was busy off photographing you must have been posting!
Here are a couple of pics unfortunately not very high definition but hopefully good enough to show a difference. One showing the equinox vase with my black light thrust in it.The other showing a UV reactive Andromeda, a non UV reactive Andromeda and my equinox vase. The light is closest to the non reactive Andromeda.
My equinox vase is frosted, as are the two Andromedas pictured.

Thank-you,
Megan

[Lustrousstone]

I wouldn't like to say. Can we have a daylight picture please of just the Equinox. The foot doesn't glow in those pix and that worries me.

[meegs]

Christine,
Here is a photo in early morning daylight of the equinox and the two ugly sisters ( actually Andromeda is a personal favourite), on the left the non reactive washed out coloured one and on the right the reactive one which I described as more spear-minty.

If I moved the light source lower or closer to the foot of the equinox it will glow, in last nights photo the light source was above and to the right of the vase.
Cheers
meegs

[Lustrousstone]

Yes, that's uranium. It may just be a slightly different composition to other pieces to give a slightly different glow.

[Moultermike]

Dear Meegs,

The fluorescence intensity is not a good guide to uranium content. You need  a Geiger counter for that. It is the UO2- (uranyl) ion which is fluorescent, while other chemical forms of uranium are not. The alkalinity of the glass, in particular, influences the amount of uranium in the fluorescent form. Higher alkalinity decreases fluorescence. Other compositional factors can also reduce it.

Moultermike_

[meegs]

Moultermike, Thank-you for your explanation it is most helpful.

Christine, I'll be keeping an eye out for one for you!

Cheers
Meegs