Post subject: The Verneuil Project - a complete collection
Posted: Tue Mar 15, 2022 2:25 pm
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Joined: Fri Jun 25, 2010 10:06 pm Posts: 2267 Location: Chapel Hill, NC / Toronto, ON
Hi all! Long time no see
I've founded a project that I think everyone will be interested in, and a bunch of members of Gemology Online have been helping out with it. It's called "The Verneuil Project"! There are two parts of the project.
Part 1 is a comprehensive history of flame-fusion gem production. The basic outline is as follows:
Verneuil's original experiments and his "sealed letter"
Verneuil's systematic chromophore experiments from 1909-1912
The founding of Djeva in 1914 (or its origins in 1903?)
The WWI shortages of alumina
The Great Depression and the closure of early firms
The late WWII experiments by Linde Air Co to grow sapphires for military equipment
The Cold War era experiments by Union Carbide, Linde Air Co, Bell Labs, and National Lead Company
The new materials developed by those same companies in the late 1950s and ealry 1960s
Transitions of other flame-fusion firms to cubic zirconia growth and technical-crystal growth
The impact of Czochralski, Kyropoulos, flux, and hydrothermal sapphire and spinel growth up to the 2000s
Shifts in production in the 2000s-2010s, from Europe to the developing world
The bankruptcy of Djeva in 2021
Part 2 is the gemological side of things. We are developing a collection of flame-fusion boules, stones, and slices. The end goal is to have every Verneuil code of flame-fusion sapphire and spinel represented, with a full boule (or split boule), at least 1x 6mm round, at least 1x 8mm square, and at least 1x 5mm-thick slice.
The Background
Flame-fusion sapphires and spinels have a numeric "code", also called the "Verneuil code", that refers to the colour and formula used to produce it. These codes come in series and usually have some kind of systematic arrangement. For example, rubies are always #01-#09 and the chromium concentration increases as the number increases. Series 30 are the blue sapphires coloured by iron and titanium. Codes 1-99 are sapphire, codes 100-199 are spinel, and codes 200-299 appear to have been experimental codes that were discontinued.
I've discussed this with elderly people from the synthetics industry, and while nobody can tell me the "real" answer, it looks like Verneuil codes were used as early as right after WWII, and some of the Verneuil codes might be related to some of the earliest experiments in chromophores. It also looks like the majority of standardization was carried out by Djeva Co., but they've gone bankrupt and I can no longer get in contact with some of their senior employees.
Over the past few decades, a lot of different colours of flame-fusion material have gone out of production. For sapphires, the cyan, green-blue, pinkish-purple, brown, and grey materials have all been discontinued. For spinels, the pink, red, orange, and purple materials have all been discontinued. Also - new manufacturing companies have started changing the codes entirely on their own, selling materials that are completely incorrect - for example, all yellow sapphires are in Series 20, but one manufacturer briefly sold them as #60! This is a crying shame - I absolutely hate the loss of this kind of history and information, and the loss of such clear standardization. So, the goal of this part of the project is to put together a complete collection of all 100% accurately-documented flame-fusion materials.
Some materials have a "rind" of one colour and a "core" of another colour. The problem with this is that it makes the final colour of the stone dependent on the orientation of the rind (table vs culet) and the size of the stone. Also, flame-fusion materials can be annealed at high temperatures, which apparently makes the colour consistently even throughout the entire boule. This obviously makes producing the collection more complicated.
I've discussed this concept privately with a few people, who are already contributing. Here's a link to a set of flame-fusion Padparadscha. Notice how the "regular" versions versus the "special (sp)" versions are a bit different, and the presence and/or orientation of the rind has an impact?
What will the collection entail?
For each identifiable Verneuil code, and for each shade NOT represented by a Verneuil code:
A full boule (spinel) or split boule (sapphire)
At least one 5mm slice, one side polished, to show presence or absence of a "rind"
Ideally, a total of three 5mm slices, one heated in oxidizing conditions and one heated in reducing conditions
At least one 6mm stone cut in "Ruination", with 0.5mm girdle, without any angle modifications
For materials with a rind, one 6mm "Ruination" with the rind in the culet, and one 6mm "Ruination" with the rind in the table, maximizing the amount of preserved rind
For materials with a rind, if possible, one 6mm "Ruination" with the rind completely removed, to show the "core" colour
At least one 8mm stone cut in "Square is Sus", with 0.5mm girdle, without any modifications
For materials with a rind, one 8mm "Square is Sus" with the rind in the culet, and one 8mm "Square is Sus" with the rind in the table, maximizing the amount of preserved rind
For materials with a rind, if possible, one 8mm "Square is Sus" with the rind completely removed, to show the "core" colour
Once complete, this collection would be sent to GIA for complete colorimetric and chemical analysis. While that won't necessarily give the full growing conditions data needed, this should give enough chromophore data so that if every flame-fusion producer in the world disappears, any random idiot with a furnace would be able to have a starting point. And, it'll give enough colour-consistency so that if you or a client wants a specific colour of flame-fusion material, you'll know exactly what to buy. After GIA, it'd go to MAGI for complete Raman, UV-Vis, etc.
What does Arya need to help complete this?
Old catalogues and documents
If anyone has any old catalogues of synthetic gems, anywhere from 2010 going back to 1950, I'd love to have scanned copies of them. I don't even know the full suite of Verneuil codes that were available!
Boules
As I'm sure you can all figure out, I need at least 3 boules of every colour. But some have long-since been discontinued. Djeva Co. went bankrupt last year and already liquidated all their stock, so I can't get some of the materials to begin with anyway. I'll post a reply to this, with a complete listing of all the codes I'm aware of. Codes in BOLD are materials that I need.
Cutters
At some point, I'll be reaching out for additional cutters to help out with this. Verneuil codes go up to #157 and if there are at least 2 finished stones from each...that's a lot of gems. And I obviously don't have the time to cut all that. Hence, the need for additional cutters.
Anyway - would love to hear people's thoughts. If you have any boules from my list, I'd love to get my hands on them!
Oh excellent, this is amazing! It looks like this German seller has the full collection of Djeva material. Let me look through my materials to see which pieces I need, and I will send you a message on here to ask for your help with translating.
Edit 2022-03-31 14:56 - unfortunately, they do not have any left in stock...
Post subject: Re: The Verneuil Project - a complete collection
Posted: Tue Aug 30, 2022 6:03 pm
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Joined: Fri Dec 25, 2015 8:31 pm Posts: 276
I hope you are able to find samples of some of those rarer numbers, with almost a century of works it feels like only the original plant could have any of some, if at all. I have seen pink spinel fragments around, but don't think they were Djeva brand...
Also reminding me to try out Ruination, now that I've lapped my copper prepolish back to flat.
Post subject: Re: The Verneuil Project - a complete collection
Posted: Sun Sep 04, 2022 4:44 pm
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Joined: Fri Jun 25, 2010 10:06 pm Posts: 2267 Location: Chapel Hill, NC / Toronto, ON
Cvergem67 wrote:
Yes, #75 corundum green Djeva is real … at least it was in the 1946 catalog. You can also add #115 Azurite, same year catalogue.
WHOA! I've never seen the 1946 catalogue. Do you have a copy of it? It would be EXTREMELY helpful for my research. I will be happy to send you a piece of #140 for FREE in exchange for a scanned copy of the 1946 catalogue. I still have about 1.5kg of pink spinel #140.
And the #60 from the Facet Shoppe gives a very nice amethyst colored gem - not what gemologists think of as prime tanzanite color (cobalt blue) but more what is peddled to the public by mass merchandisers.
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Post subject: Re: The Verneuil Project - a complete collection
Posted: Wed Sep 07, 2022 4:23 pm
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Joined: Fri Jun 25, 2010 10:06 pm Posts: 2267 Location: Chapel Hill, NC / Toronto, ON
abeck wrote:
Here are some of your missing boules:
Awesome!!! I'm sending Warren an email; hopefully there's some of SC-19 and SC-67 left that I can pick up.
abeck wrote:
And the #60 from the Facet Shoppe gives a very nice amethyst colored gem - not what gemologists think of as prime tanzanite color (cobalt blue) but more what is peddled to the public by mass merchandisers.
Hmm, this is probably mislabelled. #60 is a blue with a hint of purple, #60.1 is a pure purple slightly on the blue side, and #61 is a medium purple.
abeck wrote:
Is this really some Djeva boules???
Yes! Tom and I tried to buy a bunch of the last few pieces of Djeva production.
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