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Glass jewels or rubies? [message #16710] Fri, 17 June 2022 21:38 Go to next message
Jenneke is currently offline  Jenneke
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I have heard that it was common to use glass jewels for watches before 1935. But I would expect higher end watches like Gruen to use genuine or synthetic rubies.

What was used for Gruen movements?

If you look in the 1917 blue book they are showing jewels and rubies…
/vgforum/index.php?t=getfile&id=9418&private=0
About the rubies they say finest or fine quality. The “jewels” material is not specified. Could be the difference between genuine and synthetic rubies.

From the 1929 guild book I would comclude all jewels were at that time rubies or diamonds.
/vgforum/index.php?t=getfile&id=9419&private=0

What do you think?


You can only waste time if you forget to enjoy it - Loesje
Re: Glass jewels or rubies? [message #16711 is a reply to message #16710] Sat, 18 June 2022 01:29 Go to previous messageGo to next message
GaryM is currently offline  GaryM
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I've also heard the use of diamonds for the anniversary models.
Re: Glass jewels or rubies? [message #16712 is a reply to message #16711] Sat, 18 June 2022 02:47 Go to previous messageGo to next message
Case is currently offline  Case
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This is a great question! And does finest rubies imply not only true ruby, but something more? The pigeon blood color, virtually no inclusions.

I’ve seen lesser brands with Ruby jewels stamped on the movement, where the stones are low grade: milky and lighter color—almost pink sapphire. Never on a Gruen.

Others (eg Paul Ditisheim) stamped their high end movements “XX Ruby Jewels”. These are the color of Gruen. Strange to me that Gruen would miss an obvious trade-up opportunity by not labeling their higher end.
Re: Glass jewels or rubies? [message #16713 is a reply to message #16712] Sat, 18 June 2022 02:55 Go to previous messageGo to next message
Case is currently offline  Case
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And there’s the explanation of the “10XP” caliber listed on the Extra Precision list! Ha, another answer—thanks Jenneke! Very Happy
Re: Glass jewels or rubies? [message #16723 is a reply to message #16713] Sun, 19 June 2022 18:14 Go to previous messageGo to next message
Jenneke is currently offline  Jenneke
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Well, it is possible to test if the jewel is glass or a gemstone (sapphire/ruby). Use a diamond tester. And I understood a metal ring might have been used to secure them because they weren’t perfectly round.

First calibrate by putting the probe on a piece of glass and adjust the light to 5.
>=9 with sound=diamond
7 or 8 could be sapphire

Tried it, but the probe is a bit big for the jewels in my ladies watches. No conclusion yet. On a non gruen cap jewel it beeped as if it was a diamond. Probably genuine ruby.
Anyone have some old mens movements and care to test?


You can only waste time if you forget to enjoy it - Loesje
Re: Glass jewels or rubies? [message #16729 is a reply to message #16723] Sun, 19 June 2022 21:18 Go to previous messageGo to next message
Barney Green
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The differnence may also be synthetic and natural ruby. In this case the test would both show them as genuine.

Gruen, Gruen, Gruen ist alles was ich habe... Gruen, Gruen, Gruen is all I have...(German folklore song)
Re: Glass jewels or rubies? [message #16730 is a reply to message #16729] Sun, 19 June 2022 21:38 Go to previous messageGo to next message
Jenneke is currently offline  Jenneke
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Yeah, I guess I am searching for a way to exclude that Gruen (or the ebauche makers) used glass jewels. Synthetic rubies contain no flaws. Genuine could.

But my cal 807 movements (premo watch co rebberg-watch specialties) have very light pink jewels. Under a microscope the finishing of the keyless works side is awful. Does have bimetal balance wheel but no cut through. I would say… a cheap low quality movement.
/vgforum/index.php?t=getfile&id=9422&private=0
/vgforum/index.php?t=getfile&id=9423&private=0


You can only waste time if you forget to enjoy it - Loesje
Re: Glass jewels or rubies? [message #16734 is a reply to message #16730] Mon, 20 June 2022 03:46 Go to previous messageGo to next message
JackW is currently offline  JackW
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I've not yet run into what I suspect is glass in a Gruen. Have in other brands during the 1910s-early 20s. Especially on the AS calibers, like the AS 137 that were also used by Gruen Guild or Watch Specialties. In all the various brands I have seen glass, garnet (real or synthetic), ruby, synthetic ruby and blue sapphire and clear sapphire. I've seen historic marketing materials for garnet replacement stones and inexpensive "jewels" that could be glass. As Gary mentioned, some of the highest quality watches would use diamond for end stones on balances and escape wheels. Unfortunately, in none that I own. The diamond cap stone in Gruen's 50th anniversary watches were even faceted on the outward facing side. I had the privilege to handle Art B.'s 50th Anniversary watches, before he sold them.

All I know is based on hard work & writing by others. I can only aspire to augment this body of knowledge. If I am wrong it is because of my own failings. -me

"If I have seen farther it is by standing on the shoulders of giants." - Newton
Re: Glass jewels or rubies? [message #16736 is a reply to message #16734] Mon, 20 June 2022 13:07 Go to previous messageGo to next message
thesnark17 is currently offline  thesnark17
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It is unlikely that Gruen would have used glass jewels at any point in their history, because they were aiming to be a respected brand.

In this era of watchmaking (teens through '20s), synthetic ruby/sapphire jewels were readily available and cheap. Only if you were scraping the bottom of the barrel for cost savings - and looking to make a quick buck somewhat fraudulently - would you use an inferior material (glass, rock crystal, etc.) instead of a metal bushing. After all, it should be cheapest to build a watch without jewels, so anyone using cheap jewels must be looking to make a quick buck (from the price difference for a higher jewelled watch) and then run.

Looked at that way, it comes as no surprise that certain Swiss makers had so many brand names at their disposal. Just change your name, and the same people will buy your inferior product a second time! (A trick that has been employed in many industries and still works today...)
Re: Glass jewels or rubies? [message #16737 is a reply to message #16736] Mon, 20 June 2022 13:40 Go to previous messageGo to next message
GaryM is currently offline  GaryM
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Jenneke might be on to something with the rebberg-watch specialties line. My 23B Out o' Doors the upper cap jewel is cracked but still keeps oil, got me wondering now if another inferior material was used in place of.

How often does one see a cracked sapphire or ruby?
Re: Glass jewels or rubies? [message #16738 is a reply to message #16737] Mon, 20 June 2022 14:19 Go to previous messageGo to next message
Case is currently offline  Case
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Fairly common, actually, for balance jewels. And I can tell you first hand that a finest quality ruby in a ring is not indestructible—my class ring shows its stripes from combat. And no fine edges there to contend with shearing force.

Synthetic Ruby I believe on Aegler. They were better quality than the norm. But Gruen mostly ordered the best from Aegler. 7J Rolex much more common from 1905-1925. The smaller sizes were super expensive to finish to a high degree. I can point to several tiny Gruens on this forum that cost Gruen more to buy new than all pw movements save their finest repeaters.
Re: Glass jewels or rubies? [message #16739 is a reply to message #16738] Mon, 20 June 2022 15:52 Go to previous messageGo to next message
thesnark17 is currently offline  thesnark17
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I see a fairly large amount of broken jewels - usually on the balance, center wheel or fourth wheel (for obvious reasons). Every now and again you get one that's broken and still functional. But I am surprised to hear of a cracked cap jewel that still holds oil. Almost makes me wonder whether someone tried to seal it with shellac or something. Come to think of that, I wonder if it would work? Assuming that it's for oil retention and that the pivot doesn't contact the crack, of course!
Re: Glass jewels or rubies? [message #16743 is a reply to message #16739] Mon, 20 June 2022 19:38 Go to previous messageGo to next message
Jenneke is currently offline  Jenneke
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Still searching in the documents to find proof that all off the jewels were rubies. Not found yet. From 1939 material catalogue, clearly a marketing thing:
/vgforum/index.php?t=getfile&id=9424&private=0
In the 1926 b supplement there is a price list for spare parts. Train jewels are the last on each parts list. There are price differences.

Rubies are friction set (or in a chaton). Glass jewels sit in a mount. You can open the mount by using the correct mount opener. If you want to press a seitz ruby, that mount has to be opened with a roamer.

I showed the picture of my pink stone bridge to a very experienced watch maker. She says it has the mounts…
Those soft pink jewels seem to have more chips and little cracks too. That cal 807 movement looks crap under a microscope. The finishing is poor, it has many burrs. Not what I would expect from a Gruen… Crying or Very Sad

I think I have to remove some bridges from my spares and look underneath. Cool

What is the difference between watch specialties, guild, precision and extra precision… maybe the jewel material had something to do with it the early years?


You can only waste time if you forget to enjoy it - Loesje
Re: Glass jewels or rubies? [message #16744 is a reply to message #16743] Mon, 20 June 2022 21:25 Go to previous messageGo to next message
GaryM is currently offline  GaryM
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Jenneke wrote on Mon, 20 June 2022 19:38
I showed the picture of my pink stone bridge to a very experienced watch maker. She says it has the mounts…
Those soft pink jewels seem to have more chips and little cracks too. That cal 807 movement looks crap under a microscope. The finishing is poor, it has many burrs. Not what I would expect from a Gruen… Crying or Very Sad

I think I have to remove some bridges from my spares and look underneath. Cool

What is the difference between watch specialties, guild, precision and extra precision… maybe the jewel material had something to do with it the early years?
Easy answer, Watch Specialties is a generic basement brand by Aegler, else it would have been labeled Gruen. How do I know, well Aegler movements made for Rolex of the same ebauche are stamped Rolex on the barrel wheel. So the 807 in my 23B is a Aegler basement brand else it would have been stamped Gruen.

So yes the pecking order is correct...
1. extra precision
2. precision
3. guild
4. garbage - watch specialties
Re: Glass jewels or rubies? [message #16746 is a reply to message #16744] Mon, 20 June 2022 22:01 Go to previous messageGo to next message
thesnark17 is currently offline  thesnark17
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I wouldn't call all WSC watches garbage. The quality is lacking in some (notably the trench watches) but not in all.

Also there are some other levels. I would say that the order is:
1. Extra Precision
2. Precision
3. Guild
4. [Gruen] Guarantee
5. Premo
6. Watch Specialties Co.
7. Lavina

Everything below Guild level is hit and miss for quality. I have some really nice Premos, and some really bad ones. Ditto for WSC. For Lavina, they're all bad.

[Updated on: Mon, 20 June 2022 22:05]

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Re: Glass jewels or rubies? [message #16747 is a reply to message #16746] Tue, 21 June 2022 03:02 Go to previous messageGo to next message
Case is currently offline  Case
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I’ve even thought the dgs symbol was added on WSC (“sold under the Gruen guarantee”) was to try to reassure folks after some of the stuff seen in early teens in Premo and United. Not their best work
Re: Glass jewels or rubies? [message #16748 is a reply to message #16747] Tue, 21 June 2022 05:55 Go to previous messageGo to next message
Barney Green
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Watch Specialties is not an Aegler brand but a Gruen daughter company. Just to make that fact clear.


Gruen, Gruen, Gruen ist alles was ich habe... Gruen, Gruen, Gruen is all I have...(German folklore song)
Re: Glass jewels or rubies? [message #16749 is a reply to message #16748] Tue, 21 June 2022 12:02 Go to previous messageGo to next message
GaryM is currently offline  GaryM
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Barney Green wrote on Tue, 21 June 2022 05:55
Watch Specialties is not an Aegler brand but a Gruen daughter company. Just to make that fact clear.
Hmmm. Did Rolex use Watch Specialties? They sure do use the same ebauche, especially the 807!
Re: Glass jewels or rubies? [message #16750 is a reply to message #16749] Tue, 21 June 2022 13:22 Go to previous messageGo to next message
Barney Green
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No, at that time Rolex (Hans Wilsdorf) and Watch Specialties (Gruen) both used Aegler movements like for example the 807. This is the way to see it. Later Rolex and Gruen both invested into Aegler and became members of the board, then Gruen stepped out and in the end Aegler became Rolex. In Switzerland Watch Specialties Co. was founded in 1917 as successor to the "United Watch Co.". The Swiss Watch Specialties branch was run by Georges Goy who was at the same time the director of the "Gruen Watch Manufacturing Co". In the US the Watch Specialties Co. existed since at least 1909. End of 1920 the Swiss company has been dissolved.

Gruen, Gruen, Gruen ist alles was ich habe... Gruen, Gruen, Gruen is all I have...(German folklore song)

[Updated on: Tue, 21 June 2022 13:24]

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Re: Glass jewels or rubies? [message #16751 is a reply to message #16750] Tue, 21 June 2022 15:09 Go to previous messageGo to next message
GaryM is currently offline  GaryM
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That's some pretty enlightening information Bernd, thanks for the clarification and insight!
Re: Glass jewels or rubies? [message #16752 is a reply to message #16751] Tue, 21 June 2022 16:01 Go to previous message
Barney Green
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One addition: Watch Specialties Co. in the US definitely existed in 1907 already as some bills show that have been published in this forum.
But the "Watch Specialties Co" and "W.S.Co" branding of movements has started in 1917 with the foundation of the Swiss branch.


Gruen, Gruen, Gruen ist alles was ich habe... Gruen, Gruen, Gruen is all I have...(German folklore song)
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