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Glass Identification - Post here for all ID requests => Glass => Topic started by: flying free on March 27, 2023, 12:03:36 PM
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I've just been reading on something else and this caught my eye. Am I translating this incorrectly? or misunderstanding what's written?
And does it just pertain to uranium opaline glass?
Pressglas-korrespondenz 2005-2
https://pressglas-korrespondenz.de/aktuelles/pdf/pk-2005-2w-mannoni-opalines.pdf
Seite 132 von 276
Quote:
'In Berlin, wo Jean Kunckel als großer Alchimist gewesen war, isolierte und bestimmte hundert Jahre später
1789 ein Professor der Chemie Klaproth (1743 - 1817)
das Uran. Von Uran, als oxydierend, gibt es grüne Uranoxyde, die nicht fluoreszieren. Mehr oxydiert, gibt es
zusammengesetzte gelbe Uranoxyde mit einer grünen
Fluoreszenz. Wenn man der Zusammensetzung der
Glasmasse Natrium-Uranate hinzufügt, erhält man ein
Glas mit zitronen-gelber Färbung durch Brechung, klar
grün, leicht opalisierend durch Reflektion. Diese Dichroïsmus genannte Eigenschaft entsteht durch Fluoreszenz, die das Uran im Glas hervorruft. Blei ist ein Hindernis für die Fluoreszenz. So hat man kein Interesse,
Kristall mit diesem merkwürdigen Oxyd zu opalisieren.
Nur Glas wird also mit Uran gefärbt werden.'
Using google translate I think that reads (my bold):
'In Berlin, where Jean Kunckel had been as a great alchemist, isolated and determined a hundred years later
1789 a professor of chemistry Klaproth (1743 - 1817)
the uranium. Of uranium, being oxidizing, there are green uranium oxides that do not fluoresce. More oxidized, there is
composite yellow uranium oxides with a green one
Fluorescence. If you look at the composition of the
Adding sodium uranate to glass mass gives a
Glass tinted lemon-yellow by refraction, clear
green, slightly opalescent due to reflection. This property, called dichroism, is caused by fluorescence caused by the uranium in the glass. Lead is an obstacle to fluorescence. So you have no interest
To opalize crystal with that strange oxide.
So only glass will be colored with uranium.'
(Still wondering where the Queen Victoria bowl was made obviously and trying to work out whether it was lead glass)
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If you get rid of the ‘returns’ at the end of the lines before translation, then the translation makes more sense:
“In Berlin, where Jean Kunckel had been a great alchemist, and a hundred years later in 1789, a professor of chemistry Klaproth (1743 - 1817) isolated the uranium.
Of uranium, as oxidising, there are green uranium oxides that do not fluoresce. More oxidised, there are compound yellow uranium oxides with a green fluorescence. If you add sodium uranium to the composition of the glass mass, you get a glass with lemon-yellow colouring by refraction, clear green, slightly opalising by reflection. This property called Dichroïsmus is created by fluorescence, which the uranium causes in the glass. Lead is an obstacle to fluorescence. So you have no interest in opalising crystal with this strange oxide. So only glass will be coloured with uranium.”
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Thanks for trying to help Ekimp. What I meant was whether I was reading it correctly i.e. I read it that opaline uranium glass was not found in lead glass items. That it needed non-lead glass. Either translation is similar and I wondered whether I'd understood that point correctly.
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My reading of it would be that lead in crystal prevents the uranium from creating the familiar uranium glow we see in non-lead glass. This would make sense as lead was (still is?) used to line containers in which uranium could be stored to prevent radiation contamination, so perhaps the lead in the crystal somehow prevents the uranium from doing its stuff?
It might be worth using the Ask a Question service at CMOG / Rakow Library as they have someone who seems able to answer this type of question, see here https://libanswers.cmog.org/faq/143932
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I will Anne and thanks so much for the link :)
I suppose my basic query is whether that uranium glass QV bowl could have been produced in Britain or was it produced by a Bohemian maker not using lead in their batch. i.e. did all the big makers here use lead in their batch in the 1830s?
Or - like John Ford, were they using uranium in lead glass batches anyway? to create a colour, as they wouldn't have known about the fluorescence really then.
https://www.glassmessages.com/index.php/topic,70066.msg403520.html#msg403520
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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. :-*
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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
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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.
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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.
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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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Lead does make the metal softer and easier to manipulate. It doesn't cool quite as rapidly as unleaded glass, giving the maker a little more leeway and time during the hot work, with fewer trips to the glory hole. I believe it is easier to cut too when cold.
Less brittle is a very good way to describe it. As long as it applies to the hot work as well as the cold work. :)
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Ok, looking for something else and in the book Baguiers et Verres a Boire due XIXeme Siecle (Darnis), there are a number of French uranium glass pieces dating first half 19th. Most I've checked at a cursory glance are glass without lead. hmmm. John Ford's 1840 uranium glass must have been remarkable. I might need to check Pellatt again as I'm sure it mentioned in there that a reduction of something was necessary to stop the glass crizzling. That might have been to do with uranium in a lead glass batch.
m
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I thought I would put the question to a test with three different uranium based articles. The dolphin candlestick with opal top The Northwood Co. c.1900 non-lead based. The small footed dish probably Whitefriars c. 1900. Pretty sure lead based. The other candlestick Boston & Sandwich c. 1850s lead based. Pictured are the results using three different light sources. Regular light, long wave UV and short wave UV.
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Thanks for taking those photographs Cagney. I've been mulling over that comment in PK. I think the fluorescence referred to must mean the yellow/green effect in seen in transparent uranium glass. And so not an effect seen in opaline glass by eye/daylight. So an explanation as to why that must have been the reason why there was no experimentation with French uranium opaline glass? There was nothing different about it so no need to experiment with using uranium in French opalines? Perhaps an explanation on how to differentiate French opalines from Bohemian opalines if there is a question over identification and the item contained uranium?
I have a new grey opaline vase c.1870s I think, but Bohemian probably and that is uranium glass. But not lead glass I don't think. No indication to the naked eye that it contains uranium. I wonder why it does?
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In the PK comment the term "slightly opalizing" in conjunction with the dichorimus I think relates to the dark green not allowing much light to pass through.The first photo is of a uranium non-lead bowl c.1930, it has a enclosed openwork [reticulated] flat extended rim and shows this effect quite well I think.
Precise formula information is extremely hard to come by. Almost all mentions of formula for uranium glass just use the term uranium oxide, no clue as to which one or type. The only documented use of sodium uranate I could find is Heiseys Marigold color c. 1929 mention in an earlier thread www.glassmessages.com/index.php/topic,72470.40html (http://www.glassmessages.com/index.php/topic,72470.40html).
The three remaining photos are the exact lacy compote [princess feather] also mentioned in the thread given. Whatever dichroic effect that can be seen [toes of foot & where stem meets bowl] does not seem to be as "slightly opalized" as as the bowl rim in the first photo. In clear uranium lead glass the dichroic effect does seem to be limited. Very dependent on the type and intensity of the lighting. Red spectrum v.s. blue spectrum I surmise. Pellatt touches on this subject in his 1849 book in relation to his gold topaz. Some snippets from the book; "of a beautiful topaz tint, coloured by uranium, which became richer in hue by diminishing the usual porportion of lead and by increasing the alkali" and "but its facinating peculiarity is lost, indeed, its colourization mostly fades by candlelight".
I wonder if the grey tint in your vase is the dichroic effect trying to push through the opaline glass and maybe that is the desired effect they wanted.
note; There is no copyright on photos from Yale.
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Probably the best known lead/opal glass using uranium would be Mt. Washingtons/Webbs Burmese. For earlier examples see links below.
https://jeffreysevans.com/auction/diamond-point-sharp-diamond-omn-covered-egg-cup-pomade-24/ (https://jeffreysevans.com/auction/diamond-point-sharp-diamond-omn-covered-egg-cup-pomade-24/)
https://jefferysevans.com/auction/pressed-covered-basket-pomade-toothpick-holder-14/ (https://jefferysevans.com/auction/pressed-covered-basket-pomade-toothpick-holder-14/)
https://jeffreysevans.com/auction/pressed-petal-columnar-pair-of-canlesticks-18/ (https://jeffreysevans.com/auction/pressed-petal-columnar-pair-of-canlesticks-18/)
https://jeffreysevans.com/auction/blown-molded-snake-entwined-cologne-bottle/ (https://jeffreysevans.com/auction/blown-molded-snake-entwined-cologne-bottle/)
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Corrected links: https://jeffreysevans.com/auction/pressed-covered-basket-pomade-toothpick-holder-14/ (https://jeffreysevans.com/auction/pressed-covered-basket-pomade-toothpick-holder-14/)
https://jeffreysevans.com/auction/pressed-petal-and-columnar-pair-of-candlesticks-18/ (https://jeffreysevans.com/auction/pressed-petal-and-columnar-pair-of-candlesticks-18/)
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Thanks for taking those photographs Cagney. I've been mulling over that comment in PK. I think the fluorescence referred to must mean the yellow/green effect in seen in transparent uranium glass. And so not an effect seen in opaline glass by eye/daylight. So an explanation as to why that must have been the reason why there was no experimentation with French uranium opaline glass? There was nothing different about it so no need to experiment with using uranium in French opalines? Perhaps an explanation on how to differentiate French opalines from Bohemian opalines if there is a question over identification and the item contained uranium?
If I recall correctly there is the point that Baccarat was experimenting with opaline uranium glass. Perhaps this comment in PK is making reference to earlier times when French makers were doing their wonderful opalines and so during that period the point being made is there was no need/desire to include uranium in the batch.
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Corrected links: https://jeffreysevans.com/auction/pressed-covered-basket-pomade-toothpick-holder-14/ (https://jeffreysevans.com/auction/pressed-covered-basket-pomade-toothpick-holder-14/)
https://jeffreysevans.com/auction/pressed-petal-and-columnar-pair-of-candlesticks-18/ (https://jeffreysevans.com/auction/pressed-petal-and-columnar-pair-of-candlesticks-18/)
That's a gorgeous example. Lovely. Thank you.
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I would certainly concede there was no need to add lead to the batch to achieve the desired color. The PK comment seems to rely on the dichroic effect to achieve a goal in opal/uranium. Thus the somewhat negative attitude toward lead in the batch. What is the goal? More opacity? Lead glass seems to add a more translucent effect, due to greater refracture of light and lessening of the dichroic effect?
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As the PK comment seems to lack a certain context, I guess we have just the facts as stated. I can'y imagine that the V&A QV bowl would be non-lead glass, as its mate in the CMOG is lead glass. The photo from V&A may lead you astray because of the lighting. Lighting can be important in regards to uranium lead glass. You may find this example interesting, if not illuminating.
Pictured is an old timey real photograph c.1991. I took this photograph under incandescent light, no flash. I know for a fact that the pillar molded and cut vases in the photograph are the exact same vases pictured in this linkhttps://jeffreysevans.com/auction/pillar-molded-and-cut-pair-of-vases/ (https://jeffreysevans.com/auction/pillar-molded-and-cut-pair-of-vases/) The presentation noticeably different?
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ah, thank you! I obviously didn't read the Corning information if it was on there. Thanks so much.
Also yes the photographs. The Corning has one which is not lit iirc but it's still hard to discern what the colour is really like. It's quite difficult to compare colour unless seeing comparisons in real life I think.
Thank you for that Cagney. So info so far on the V&A bowl - it's lead uranium glass, and apparently produced by Davenports at very short notice to supply for the Coronation banquet held at Guildhall in November 1837.
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I think Siegmar may have meant to say that when you set out to colour a piece with uranium you better use standard glass. No need for lead crystal to bring out the colour. But I have a finger bowl from Baccarat around 1840 which is high quality crystal with uranium, turning it into Chrysoprase, an opaque opaline. I also have its companion, high quality dark green lead crystal. FWIW.
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This is a good description of why uranium glass fluoresce.
https://www.popularmechanics.com/science/a39995070/why-does-uranium-glass-glow/#
The UV causes an electron in the uranium atom to jump up a number of states (ie excited) as the electron drops back to its ground state (state by state) it can give off photons of lower energy.
And here are a few other materials that also cause glass to fluoresce.
https://libanswers.cmog.org/faq/143932
Different energy levels between the different states is why the colours vary by material.
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Thank you Ivo :) Would love to see your dark green uranium Baccarat finger bowl to make a comparison to my tumblers of same period.
Thank you Taylog :)
Interesting comment in that article in the link to Library CMOG (my bold - see quote below), in that I am pretty sure my old tumblers are lead glass and they're both green. Have I misunderstood what I'm reading?
'Leaving out the exotic elements not found in ordinary glasses, the responses are more-or-less as follows:
U (Uranium)-- A very strong bright-green response. The color of the glass itself in visible light is usually a bright yellow or yellowish-green, or an amber color in a lead matrix[/b]. ...'
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Barrie Sketcher mentions lead glass weakening the uranium fluorescence from uv light. Page 3 para 3: https://www.glassassociation.org.uk/sites/default/files/Uranium_Glass_sample_article.pdf