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 Post subject: Ruby Surface diffusion confusion
PostPosted: Sun Aug 06, 2006 1:58 am 
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Here I am studying up for my colored stone exam on the road to my GIA GG, and a question comes to me. Is ruby surface diffusion to deep to be harmed when buffing jewelry with stones in place? Just curious…

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PostPosted: Thu Aug 10, 2006 12:12 am 
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Hello Danielh,
i come across that when the Ruby with glass filll, after setting when wash by acid for the final process.
the glass may come out and can see a vary clear crack mark and can feel it by finger.
Thanks.

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PostPosted: Thu Aug 10, 2006 8:26 am 
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I would expect that the diffusion treatment is deep enough to be safe from a buffing for a couple reasons.

First, it was my understanding that diffusion treated sapphires are polished after the treatment -- if the diffusion zone is deep enough to handle a polishing process, the buffing likely won't harm the colored zone. (If you're removing *that* much stone with your buffing, you really should just buy a faceting machine. :wink: )

Second, corundum is hard stuff. Polishing is done with diamond. I would expect that the buffing compound used to polish metals will not affect the corundum, treated or not. (Hopefully someone more experienced will correct me here if I'm wrong.)

peter

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PostPosted: Thu Aug 10, 2006 10:23 am 
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It is my understanding tht the early diffusion treatments were very surficial and repolishing could often remove them.
The science has been improved and now the color is often changed throughout the courundum.


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PostPosted: Thu Aug 10, 2006 10:23 am 
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Surface diffusion typically has a penetration from 0.01mm to 0.50mm. The process involves heating the corundum and the diffusion elements to near melting point of corundum. Sometimes this sinters the surface of the corundum and it has to be re polished.

Heavy handed polishing could remove the shallow layer of diffused color.
I would think buffing would not have that effect as pt pointed out.

Of course we are talking about typical situations with the typical treatment results.

P.S. We were typing at the same time Barbra. Yes newer treatments can have a more thorough and complete penetration. So it is correct to make the distinction between "Surface" diffusion and other methods. :)


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PostPosted: Thu Aug 10, 2006 1:54 pm 
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I would imagine the treatment should, or would be deep enough into the surface. But now reading here, I am wondering what the friction heat from buffing would do. Now it would have to be an over zealous buffer, but I have experienced that personally in the past.
Many moons ago, in the past, I had a few occasions while buffing jewelry I stayed on the buffer so much that the piece became so hot that a joint fixed with easy solder came apart. Since those timesIve stopped the leather wearing finger protection when buffing. Now when if I stay on the buffer to long, I find out in time. !Ouch! :oops: So , I also wonder if something like friction heat could damage treatment?

Im just thinking of all kinds of things today aint I??
:roll:

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PostPosted: Wed Aug 16, 2006 7:16 pm 
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Ok, found it later in my studies for the colored stones test. Surface diffusion can be buffed out if it didn’t penetrate the surface very deep. But, a facet re-polish of the stone can remove it, and refaceting surely will.

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PostPosted: Fri Aug 18, 2006 12:28 am 
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Hi Regarding ruby there is no surface diffusion treatment as chromium is very fiddicult to diffuse in corundum. The treatment called surface diffusion for ruby is in fact a synthetic overgrowth process.
If I remember well there have been an article written possibly in gems and Gemology if I remember well by Christopher Smith about this subject.

To my understanding there is not problem to set such stones on jewelry.

All the best,

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