A question about jeweling.

Old rookie

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I was thinking (a dangerous activity for me without adequate adult supervision) that some makers offer movements with ruby jewels on some movements and sapphire jewels on others. Both stones are of equal hardness on the Mohs scale at 9. (diamond at 10 is the benchmark). Did each stone have some other unique property that appealed to watchmakers?
 

musicguy

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color


Rob
 

Old rookie

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Thanks Rob, that covers the cosmetics but what about cost? I imagine sapphires were as cheap and plentiful then as now. Rubies, not so much.
Wouldn't production costs be lowered by standardizing on sapphires? Yet in a Hamilton parts list ruby,sapphire, and garnet are listed as replacement jewels.
 

musicguy

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Some high end watches have diamond end stones.

maximus.jpg


Rob
 

musicguy

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I was aware of that. ;)
I figured, but it gave me a chance to show a photo of a nice diamond endstone(even if it is quite small). :)


Rob
 

DeweyC

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I was thinking (a dangerous activity for me without adequate adult supervision) that some makers offer movements with ruby jewels on some movements and sapphire jewels on others. Both stones are of equal hardness on the Mohs scale at 9. (diamond at 10 is the benchmark). Did each stone have some other unique property that appealed to watchmakers?
It may depend on the "facts" of the 19th century. For example, traditionally, sapphire is the stone for the 45th wedding anniversary while ruby is the stone for the 40th.

Early Hamiltons used ruby pallet and impulse stones in the non RRG movements and sapphire in the RRG movements. Could it have been assumed greater transparency and clarity were evidence of greater crystal integrity?

(Edit) I just emailed the curator at the Smithsonian Dept of Mineral Sciences.

I tried Google to get a sense of the comparative historical value of the two. I did find this :


It contains a graph that seems to indicate that sapphire commanded higher prices over the period of late 19th early 20th century. Ruby did reach a peak of similar pricing but for a very short duration. Hard to interpret because the size is small.

I am not sure when chemical analysis demonstrated the two stones shared the same physical characteristics with different dopants that produced the colors.
 
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Al J

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Thanks Rob, that covers the cosmetics but what about cost? I imagine sapphires were as cheap and plentiful then as now. Rubies, not so much.
Wouldn't production costs be lowered by standardizing on sapphires? Yet in a Hamilton parts list ruby,sapphire, and garnet are listed as replacement jewels.
Are you referring to natural stones or man made? The difference between sapphire and ruby is just the impurities in the corundum - ruby has chromium for example. Ruby is always red, but sapphires can be pretty much any other colour. Blue is what most people associate with it though.

Stones have been manufactured for a very long time, and in different colours. Several years ago I was in Glashütte in Germany, and they have a great museum of German watchmaking there. I took this photo of jewels that had been made and used at the school in the past, and you can see the colours vary widely:

German jewels Glashutte1.jpg

If you are ever near Dresden, taking the short train ride to Glashütte is well worth it. I've been all over Switzerland and through many factories, but you won't find a more concentrated place of watchmaking than in Glashütte.

I don't think there's a practical difference in watchmaking terms. I've seen lots of red jewels of course, but also plenty of colourless jewels, and the occasional blue jewel.

Cheers, Al
 

D.th.munroe

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I think one reason for advertising Ruby or Sapphire, was the amount of lower quality stones like garnet and glass being used at the time.
Dan
 

Harvey Mintz

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As far as the cost difference between Ruby and Sapphire, byt the 1880's almost all the non-diamond jewels used in watches would have been synthetic, since they were just as good quality (from a watch maker's perspective) as natural stones, but cost a lot less. This time period also corresponds to the "Great Upjeweling Race", where more and more jewels were put into watch movements as a way to distinguish some movements as higher quality, leading to as many as 25 jewels being installed in some time-only movements.
 
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