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Author Topic: Some questions regarding UV glow of Uranium- and other glass  (Read 633 times)

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Offline rocco

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Some questions regarding UV glow of Uranium- and other glass
« on: August 30, 2012, 07:20:55 AM »
I borrowed the UV torch from work the other day, and tested my glass -- which led to some interesting observations...

It was not much of a surprise that almost all my 1950s Skrdlovice pieces containing green colour glowed brightly (pic 1 shows some of them), the same with the green in my Exbor fish.

But in several pieces even the colourless glass showed distinctive green fluorescence (Skrdlovice Andromeda vase, pic 2, and several of my Murano pieces like the Barovier & Toso fish - pic 3, and the tall smokey grey still unattributed vase pic 4).
Even the amethyst-grey casing of this vase glowed brightly.

My amber Daum etched bowl glows green as well, though more obvious in the parts where the glass is thicker...

To my surprise my green A. Seguso bear didn't really glow brightly -- it looked almost the same under UV than in natural light.

So are there different levels of Uranium content in glass? And why would colourless glass contain Uranium? Does a green glow always indicate Uranium content?

Thanks for any comments,
Michael



Offline chopin-liszt

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #1 on: August 30, 2012, 08:45:02 AM »
The pale "glow" is not uranium, but Manganese which was used to reduce the effects of colouring from iron in the metal (I think that's it's use - but it is definitely manganese that gives the green colour with UV light.)
Cheers, Sue (M)

“All things are subject to interpretation. Whichever interpretation prevails at a given time is a function of power and not truth.” Friedrich Nietzsche


Offline Lustrousstone

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #2 on: August 30, 2012, 11:57:13 AM »
I suspect most of them contain manganese not uranium, possibly even your Exbor fish, as it's green doesn't look right for uranium. Did you test them in daylight?

Your green Skrdlovice pieces might contain uranium, but it would be unusual and I would like to judge them without UV.


Offline flying free

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #3 on: August 30, 2012, 12:06:15 PM »
Christine I sometimes find it really difficult to get my camera on the right setting where it will properly replicate the bright green glow on u pieces.  Could that be the case here maybe?
m


Offline Lustrousstone

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #4 on: August 30, 2012, 12:08:16 PM »
Not with the non-green ones


Offline rocco

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #5 on: August 30, 2012, 04:46:57 PM »
Thanks for sharing your knowledge, very interesting! :)

We had already several pieces in our Skrdlovice thread where the green glass glowed brightly under UV, and the common sense was that these contained Uranium >> Link
In my cut pieces from Skrdlovice blanks the green glow is even obvious in daylight >> Link

When I tested my glass many of the colourless pieces showed some vague glow in a greenish-yellow colour; but in the ones I showed the glow was much stronger (especially the tall vase in my last pic glows obviously green, and a slight greenish hue is visible in daylight as well).

So do the colour plus the amount of glow indicate if the glass contains Uranium?

Michael


Offline chopin-liszt

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #6 on: August 30, 2012, 05:00:59 PM »
Yes! Lots of glow from even the tiniest bit of Uranium.
It can be very hard to capture on camera because the glow itself emanates.... makes all your edges funny and fuzzy.
Cheers, Sue (M)

“All things are subject to interpretation. Whichever interpretation prevails at a given time is a function of power and not truth.” Friedrich Nietzsche


Offline Lustrousstone

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #7 on: August 30, 2012, 05:05:24 PM »
It's not the amount of glow; it's more the colour of the glow. Uranium gives a very bright green glow under UV in daylight no matter how little or how much uranium. It's the same brightness just sometimes more dilute (it's very difficult to explain).

Manganese gives a dull glow and the more manganese the greener it is. I have been trying to persuade myself for a long time that this piece contains uranium (in the base and handle) because you can see green in the base in daylight without a UV light, but I'm sure I'm just fooling myself
http://lustrousstone.co.uk/cpg/displayimage.php?pid=491

What I'm trying to say is that I wouldn't like to say yes to uranium from your pictures


Offline rocco

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #8 on: August 30, 2012, 05:11:02 PM »
Thanks again!
More difficult to jugde than I had thought then...

So maybe none of them Uranium glass, even the (daylight) green coloured pieces?

I have one Murano piece (>> this corroso ashtray) which glows like mad even with the UV torch 2 metres away, so this should be my reference then I guess...

Michael


Offline Anik R

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Re: Some questions regarding UV glow of Uranium- and other glass
« Reply #9 on: August 30, 2012, 05:51:29 PM »
Quite a few of my Skrdlovice pieces give off a dull greenish glow when I shine a UV light on them in the dark, but only 2 shine brightly, even when I stand a couple of meters away, even in daylight.  Those two undeniably contain uranium.

I think the 'stand further away and shine' technique is a good one for distinguishing a manganese glow from a uranium flare.  :)
My Etsy shop with Czech glass: CzechGlassCollector

 

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