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AIGS ability to test for diffused corundum
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Author:  Barbra Voltaire, FGG [ Mon Jun 07, 2010 12:39 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

tudortwo wrote:

I don't know that is true Jason. I'm trying to find out, but when I emailed the lab, and asked them if my gem was only heat treated without beryllium because it said HT only, they just said that the "issue of beryllium was not addressed."

I would interpret that to mean, that there was microscopic evidence (alteration of inclusions) indicating heat treatment, but LA-ICP-MS was not performed.

tudortwo wrote:
If that's true, they should remove their HT codes from their webpage because it is misleading.

Why is it misleading? Corundum heat treatment is not synonymous with light element diffusion.

tudortwo wrote:
I could potentially sell this gem, which might be be-treated, as traditional heat only by referencing that web page to a buyer.

I think most buyers would specifically request LA-ICP-MS if they wanted to be assured there were no traces of light element diffusion.
I suspect it is not routinely done because it is a costly test, requiring very sophisticated technicians.

Author:  Jason [ Mon Jun 07, 2010 1:54 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

I would like to add that it was pointed out to me that sometimes (apparently commonly enough where it's taken into consideration) Beryllium can be present in the corundum when there are *no signs of diffusion process*. In these cases the beryllium is naturally occurring.

Author:  Alberto [ Mon Jun 07, 2010 3:17 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

Barbra Voltaire wrote:

I suspect it is not routinely done because it is a costly test, requiring very sophisticated technicians.



Agree, aandd...we must remember that LA-ICP-MS test (like LIBS, same ablation process) is a partially destructive test cos the laser must vaporize tiny spots in order to have plasma which must be analyzed by the Mass Spectrometer. usually the ablation is performed just under the gridle (for polished stones) and, for what i know, more tests are performed in different parts of the stone in order to have consistent values. So, since we're talking about a semi-destructive test a written authorization by the client is required.

ciao
alberto

Author:  tudortwo [ Mon Jun 07, 2010 8:50 pm ]
Post subject:  Re: AIGS ability to test for diffused corundum

Well, to me, when they say "the issue of beryllium was not addressed" I believe that they mean that they just didn't test for it, and it could very well be be-treated. I tried asking for clarification, but received none. The reason I think the HT codes on their site are misleading is because based on the HT code on my memo, I had thought this just meant traditional heat treatment. Evidently, it could be otherwise?????.

All diffused stones are heated, but not all heated stones are diffused, so doesn't that mean a heated stone can also be be-heated? I did not request they check for be-treatment because I had assumed, based on the HT codes on their website, that they automatically test for it, and they had the machine to do it. That was my fault, but the page did mislead me.

I mean, if they found evidence for traditional HT treatment microscopically, would they need to conduct the expensive test for diffusion? Can you determine traditional heat only with standard gemological equipment??

On their website they have several HT codes and some of them have parentheses that show if a stone has a foreign element. The code HT, all by itself, I have interpreted to mean traditional heat only.

Author:  Barbra Voltaire, FGG [ Mon Jun 07, 2010 10:01 pm ]
Post subject:  Re: AIGS ability to test for diffused corundum

Quote:
I did not request they check for be-treatment because I had assumed, based on the HT codes on their website, that they automatically test for it, and they had the machine to do it. That was my fault, but the page did mislead me.

I understand how you misunderstood exactly what was being tested for. I'm sure you are not the only person who is confused about this. It would be very helpful if labs made it VERY clear that additional testing is required to verify the presence of light element diffusion....and it would probably increase their bottom line if more people required it.

But, now you know.
And, if you use AIGS or a different lab in the future, I'm sure it is a question you will ask before submitting a gem.
Quote:
I mean, if they found evidence for traditional HT treatment microscopically, would they need to conduct the expensive test for diffusion?

We've answered this already. Yes.
Quote:
Can you determine traditional heat only with standard gemological equipment??

Sometimes, if there has been visible and diagnostic alteration of the inclusions indicative of heat.
If there are no inclusions it can be impossible to detect.

Hope this helps. :D

Author:  Olivier [ Sun Jun 13, 2010 7:15 pm ]
Post subject:  Re: AIGS ability to test for diffused corundum

I heard many things from AIGS Lab and school those last days...
I think I know why there is no much answer from your demand to the lab...

Wait and see.

Oli.

Author:  allen [ Sun Jun 13, 2010 10:48 pm ]
Post subject:  Re: AIGS ability to test for diffused corundum

Now that's pretty cryptic.

Author:  tudortwo [ Sun Jun 13, 2010 11:50 pm ]
Post subject:  Re: AIGS ability to test for diffused corundum

Thank you for the reply Barbra. You see, my hope is that the fact it says HT indicates that they saw no reason to send it to another lab to test it for diffusion. However the AIGS seems to be skirting that question, and will not definitively answer it. I have asked them that outright. It's depressing to me because I have this lovely pear sapphire that I want to set, but knowing that there's a possibility it could be diffused has ruined the gem for me. I also do not want to send it to a more expensive lab in the States to get another certificate indicating the treatment level. I bought the stone from Asia, and the AIGS report was part of the price.

Here is the stone in question and a photo of the gem brief. It is obviously not top color, but I do think it's pretty and worthy of setting, if I only knew it wasn't treated. The second photo includes a 1.1 carat spinel that I was planning on doing a bypass ring with this stone. Obviously, no one can really tell if it's been treated from the photos, but I just wanted to show everyone, so they can share in my anguish over this dilemma. LOL!

Image
Image

Here is a screen capture of the vendor video. The stone shows some minor zoning in the video, and as you can see here, it has a slight violet cast, which I know is not ideal, but I like it. It shifts to a more violet in certain lighting, like this.
Image

Author:  Barbra Voltaire, FGG [ Mon Jun 14, 2010 12:06 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

Oh. =P~
That's a really pretty saph.

Author:  studiogem [ Mon Jun 14, 2010 1:23 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

mmm...maybe im missing something...so if i dont request for a specific test then the stone will only be analized on the microscope and so only "conventional" enhancements can be disclosed...

if this is the case then i find it a bit tricky...
when a stone passes the door of a gemlab, it is tested completely till you have a final result about the nature and the treatments/enhancements...it doesnt matter if any further test is needed.
just infom the client about the extra costs and "distructive" tests.

and if he doesnt want then you return it without results.
a generic "heat treated" doesnt help customer confidence nowadays.

ciao

Author:  Alberto [ Mon Jun 14, 2010 5:04 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

Hi,

studiogem wrote:
just infom the client about the extra costs and "distructive" tests.


Agreee about what you said but I would ask before rather inform....

ciao
alberto

Author:  studiogem [ Mon Jun 14, 2010 7:18 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

..right...this is what i meant..inform them to get the permission..
:)

Author:  Barbra Voltaire, FGG [ Mon Jun 14, 2010 9:47 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

An LA-ICP-MS or SIMS unit can run from $150,000 to $300,000, and routine maintenance like replacing a laser can be another $25,000 to $30,000. Tests on these sophisticated units must be performed by highly trained individuals. Gemological schools do NOT train students to use these machines (with the exception of SSEF) SO labs need to find qualified candidates to run them. These are usually individuals with advanced university degrees. Therefore, they too are expensive.

A university routinely charges $500-$600 for a LA-ICP-MS test to be run on a mineralogical sample, and that is about what most Gem Labs must charge as well. Most folks are not willing to invest this money on testing unless they are reasonably sure the gem they possess has not been diffused with light elements and hope the testing charges will be recouped in the final sale price.

Author:  Olivier [ Mon Jun 14, 2010 10:41 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

Hello all,

When I was at the AIGS we had few discussions about the Be treatment and I remember clearly that the AIGS lab was not only making research on Be treatment but for some other light elements as well. As we know that today, some people in Thailand are trying to heat stones with other stuff to get maybe new nice colors?

So, I am surprised that today they could not do it. Now, if the leader of this lab is not there anymore, maybe they cannot keep going with those research or analysis. I am waiting for answer about that…

Now I am agreeing on the fact that when you send a stone to lab, especially when it's a sapphire, you have the right to expect that all the tests should have been done and you pay for it. No lab can release a stone labeled Heat Treated only if the stone have been Be treated too, and if they cannot run the test, then the customer MUST be awarded. On the market, a HT stone have a price and Be stone have an other price, and at the AIGS lab they now that for sure. I can’t imaging that the lab will release a stone Be treated just saying it’s HT. it so important today in the trade!

If I have direct and clear answer and news about what’s happening in the lab. I‘ll keep you in touch.

Author:  Barbra Voltaire, FGG [ Mon Jun 14, 2010 10:47 am ]
Post subject:  Re: AIGS ability to test for diffused corundum

It is my understanding that AIGS does not own a LA-ICP-MS unit themselves, but worked with facilities that had one if necessary.

Olivier, are you aware of any lab which tests for light element diffusion as a standard part of a $100 identification report?

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