Glass Message Board
Glass Identification - Post here for all ID requests => Glass => Topic started by: NevB on January 15, 2022, 12:02:33 PM
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These are the first pieces I've found with crizzled surface. It depends on the angle of viewing whether it's visible and held up to the light it disappears. Both have ground pontils, one larger, and I think they are probably mid 19thC. possibly by Richardson.
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very nice - take your word for it re the age :) Is this crizzling in the Ravenscroft sense i.e. loss of transparency, or does the glass weep ................ surprising that a maker such as Richardson should make an unstable batch, but suppose it can happen to anyone. Do you think this might be a case that these weren't annealed in the lehr correctly?
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Those are definitely in the early stages of crizzling. I have one or two. I've always felt that lovely shade could be Percival Vickers but...
http://lustrousstone.co.uk/cpg/displayimage.php?pid=1426
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Paul, they don't show any cloudiness or weeping just a very fine "cobweb" appearance and speckling. Apparently it's caused by an excess of alkali or lack of stabiliser, perhaps the mix only has to be a little bit out to cause it. I thought they had the look of Richardson but they could be by someone else, I've got a few others in this nice colour.
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Crizzling. Cannot be felt on the glass. In the beginning hardly noticeable in diffused light, shows up in direct light especially at certain angle. Severe case will cloud the article no matter the light. The term "cobweb" effect is very apt. I have used the term " a fine lace-like effect ". I think I will change my terminology.
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Thanks cagney, I can't take credit for the cobweb description, I read it online. My glasses seem to have two different problems, the cobweb crizzling which can best be seen looking from inside the glass and the speckling which, for some reason, is only on the cut surfaces.
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Not quite sure what speckling is in this context. I would hazard a guess and assume some sort of obscuring feature in random or haphazard manner? spattered?
I would think the cut portions may be more susceptible to other degradations brought about by the fact that it may absorb a little different than the original annealed glass around it. Just a theory. More pictures?
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More photos of the speckles which also appear on the foot to a lesser extent.
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That's a type of crizzling I think . A degradation of the glass. I have seen it on quite a lot of old opaline glass as well. I avoid buying if I see it in the photos.
m
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I don't mind it m, it's interesting and adds to the character and they weren't expensive :)
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Can the speckles be felt on the glass? Where as the other crizzling cannot?
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Yes I can feel the speckles but not the crizzling, it seems to be two different forms of glass "sickness".
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Sickness or sick glass is the term used over here [U.S.A.] as well.
The authors Raymond E. Barlow and Joan E. Kaiser devote two pages to a form of this sickness in one of their " A Guide To Sandwich Glass" books.
Interestingly, they did an experiment using two pressed glass alabaster lamps c. 1840-1860 in a deteriorating state with all over roughness to the touch. They put both lamps on separate black velvet mats, placed one in front of a window and the other in a display case against a back wall where light and temperature fluctuations were minimal.Both lamps were undisturbed for a year. At the end of that time "hundreds" of minute particles of glass had fallen from the lamp in the window. They glistened on the upper surface of the base and the black velvet. Some flakes were larger than the head of a straight pin and were more than eight inches away from the lamp, indicating they had literally snapped off the surface of the lamp. Flaking did not occur on the underside of the base or inside the font/reservoir. The lamp in the display case against a back wall had
shed perhaps fifteen flakes that had fallen from the outside surface, onto the lamp base and velvet.
They then washed the lamps and reversed there positions. A year later they again examined them. The same results more or less were attained.
There seems to be various forms of deterioration depending on the source of the problem. One 19thc. account is in Apsley Pellat's "Curiosities of Glass Making" c. 1849. He states that an excess of alkali caused the cementing property of the glass to escape, " entire fracture is the result and no remedy will check the evil".
Crizzling is different. It is inside the glass and actually is a series of minute lines that interconnect with each other and as a result reflect light. Pictured are details of early 19th c. crizzled lead glass vase.
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Interesting lamp experiment and also clarification of the terminology of crizzling.
Apsley Pellatt had to replace an entire delivery of uranium glass because the customers complained it had disintegrated (iirc a few short months after delivery). I think he said that was due to lead content? From my reading there seems to have been experiments to reduce the amount of lead in uranium glass giving a different /better colour but I guess he learnt the acceptable baseline :)
I had a large egg-shaped paperweight that was damaged but looked as though it was just pitted. Kev said he thought it was Chinese.
I left it in a glass cabinet for a couple of years and then a few months ago was changing things around and found the glass surface was flaking off it in big chunks. Some much bigger than a pinhead, quite a few mm in diameter round. I chucked it but it was an interesting journey :)
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as a matter of interest m, do you know the date when Pellatt experienced this problem?
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Unfortunately no! Annoying because I'm curious.
He writes very little about uranium glass and I'm not entirely convinced they made lots of it. Mind you I'm saying that but as I type this I'm thinking 'was he talking about producing Topaz glass or uranium glass?'. And I don't think I've got to the bottom of whether what he calls Topaz glass was actually uranium glass or was in fact just amber coloured glass not coloured with uranium oxide. See my post below
His book was printed in ?1849? I think.
I can have another read a bit later and see if I can help further but I don't think I can because I've been over and over it in conjunction with researching the Queen Vic bowl which supposedly was produced for her Guildhall dinner in 1837.
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Have checked :)
Yes he said
'A large quantity of Flint, or compound Glass, manufactured at the Falcon Works, (of a 'beautiful topaz tint, coloured by uranium, which became richer in hue by diminishing the usual proportion of lead, and by increasing the alkali,) fractured three months after it was cut.'
His entire short para on this bit implies the glass had been cut. No date or period is implied or stated. However to be honest, if your factory had spent a fortune producing uranium glass in the batch and then had to replace the entire 'home and abroad' shipments at your own expense, it wouldn't be an event you'd forget and could still be talking about it years later. So ... no known date. Book printed 1849
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Report 1847-1848 from the Pharmaceutical Journal and Transactions Vol VII - printed 1848
page 448
report on Apsley Pellatt lecturing at the Royal Institution - supposed to have happened on Feb 11 (1848 I think) but the furnace burnt the floor and they had to abandon at the last minute and move the talk to Feb 18 according to this report:
In the report it says Pellatt said (?) that apparently an excess of alkali meant the uranium glass 'after some time, became opaque and rotten'.
https://www.google.co.uk/books/edition/The_Pharmaceutical_Journal_and_Transacti/QcDq5dmfflsC?hl=en&gbpv=1&dq=mr+pellatt+uranium+glass&pg=PA448&printsec=frontcover
I can't tell you what date the uranium glass he made (or used an example of from somewhere else maybe? that is not clear really) became opaque and rotten however it is strange he's still lecturing and mentioning it in 1848 (referring to the Queen Victoria bowls apparently being made in 1837 obviously). I'd have thought that if uranium glass was being freely and easily produced in 1848 there would have been no need to mention. That is making an assumption of course. He could have just been chatting about a long forgotten pre 1837 episode