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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Mon Jun 14, 2010 4:01 pm 
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Unhappily no as I send my important stones in Switzerland where nothing is cheap...

Oli.


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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Mon Jun 14, 2010 9:45 pm 
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Barbra
GRS do for that amount in Bangkok.

Im not sure about LA-ICP-MS or LIBS but they do test for light element plus Origin for around $100


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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Mon Jun 14, 2010 10:23 pm 
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How are they testing for it?
Can you find out for us?
Thanks.

Update.
I went to their site in Bangkok and it appears the determination is made microscopically. Please correct me if I am incorrect here, as I think the sophistication of light element diffusion has, in many (most) cases, has made microscopic determination somewhat obsolete.
Direct Link= http://www.gemresearch.ch/news/RepNewTr ... reat-E.htm
GRS Lab Bangkok wrote:

GRS policy on the reporting of the new treatment applied to Fancy sapphires of various colors:

Case A. Fancy sapphires with the following characteristics: Orange-pink to red colors face-up, center of the stone and rim are different colors visible:

ID: Natural Fancy Sapphire
e.g. Color: orangey-pink (pink core and orange rim)
e.g. Color: red (purplish-red and orange rim)

Comment section:
H(Be) Enhanced by heat and light elements (e.g. Beryllium).
Research reference see Internet: http://www.gemresearch.ch/journal/index.htm

Padparadscha and Ruby* reports will not be issued for gemstones with orange rim confined to the surface.

Ruby certificates for Be-treated corundum may be given exceptionally, but if, it will be provided with the additional comment under the comment section:

*Be-treatment produced a considerable color enhancement from a "fancy color" towards "vivid red”.

Natural Orange Sapphire

Comment section:
H(Be)
Research reference on the Internet: http://www.gemresearch.ch/journal/index.htm

Full description of the treatment is given on the reverse side of the report as (with a remark on the front page on important information on reverse side):

H(Be) Enhanced by heat and light elements (e.g. Beryllium).
Clarity and/or color are enhanced by heat and diffusion of light elements such as Beryllium, inducing color zoning by internal migration of trace elements (incl. Beryllium) and defects, and formation of color centers. (Not corresponding to conventional surface diffusion treatment), Treatment is permanent. Recutting requires special care if thin orange rims are confined to the surface. See Internet publication
http://www.gemresearch.ch/journal/index.htm.


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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 4:28 am 
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This is weird to me too. Maybe I'm missing something but as far as I understand it light element (bulk) diffusion penetrates the stone and is not limited to a rim. IE it is not surface diffusion. Sometimes one can be lucky with immersion, especially with older treated stones, but you could never rule out the treatment based on the lack of positive results under immersion or microscopic examination. Surface diffusion was generally performed on cut stones that were later polished in order to preserve the treated colours. New advancements allow the rough to be treated because the is no longer an issue. This fact alone makes me wonder how they can use only those techniques to test for it.


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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 4:50 am 
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Lukeness wrote:
This fact alone makes me wonder how they can use only those techniques to test for it.


Yep, and, again, i tested many parcels of Be-treated stuff, many stones showed absolutely NO evidence of diffusion nor of High temp heating...... :roll:

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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 6:47 am 
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Alberto wrote:
Yep, and, again, i tested many parcels of Be-treated stuff, many stones showed absolutely NO evidence of diffusion nor of High temp heating...... :roll:


Are you saying that you have Beryllium treated stones that are not treated with high temp heating? IT was my understanding that low temp was not adequate.

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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 6:51 am 
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Jason wrote:
Are you saying that you have Beryllium treated stones that are not treated with high temp heating? IT was my understanding that low temp was not adequate.


no, i'm just saying i tested many parcels of Be-treated stuff, and many stones showed absolutely NO evidence of diffusion nor of High temp heating......

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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 7:12 am 
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How then can a stone be determined to be BE treated and not containing naturally occurring Beryllium? I thought any stone with beryllium that shows no signs of diffusion could not be considered enhanced with light elements. I'm not getting how the determination is to be made based on your experience.

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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 7:19 am 
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I guess what i'm asking is even if BE is detected with LA-ICP-MS or LIBS, where there is the absence of evidence of diffusion, what is to determine that these gems have been treated beyond standard heat treatment since sapphires with beryllium are known to naturally occur?

I don't know this as a fact, but i would guess that sapphires with naturally occurring beryllium would behave similarly during heat treatment to those without natural beryllium but heated with light elements at high heat. In other words, that you would end up with similar colors with traditional heating methods.

Long and short, the presence of Beryllium does NOT prove the gem has been diffused.

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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 7:35 am 
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Jason wrote:
I thought any stone with beryllium that shows no signs of diffusion could not be considered enhanced with light elements. I'm not getting how the determination is to be made based on your experience.


Jason,
i'm only sharing my experience here, i got some parcels from different wholesalers, all the material was claimed to be BE-diffused, i saw in many stones clear evidences of HT but not in all of them (a mistake could always occur, of course but i see no reason why there could be untreated stones in BE-treated parcels... :wink:..we're not talking about 1 stone here, the parcels were consistent) , you know, microscopically speaking, you can spot HT heating by observing modifying of the internal inclusions so, if you're not able to spot them (reasons could be many) you cannot simply assume they're treated.

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what is to determine that these gems have been treated beyond standard heat treatment since sapphires with beryllium are known to naturally occur?


i guess it's a matter of concentration of the element, i'm not sure the amount of BE present in some parts of the treated stone is the same recoredered in naturals (LA-ICP-MS provide for quantitative values).... :roll: but i'm not an expert about that kind of advanced tests so, like you, i' would be more than glad to hear a bell from skilled people... :wink:

ciao
alberto

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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 8:30 am 
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natural content of Be in natural sapphires is a matter of few ppm.
i assume that this quantity is spread all over the stone.
if i test the sapphire with LA-ICP-MS or LIBS, i have a "external" analisys of the stone and normally the result is a evident presence of Be (not just few ppm), and i can test in different spots to confirm the "rim".

i think this is enough to differentiate natural Be/diffused Be in sapphires.

unless someone has different experiences :)

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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 10:00 am 
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I would agree with Alberto and studiogem on that. Some time you can't just see anything on the stone and it can be Be treated. Have to trust your trader, but usually the price tell you many things... On the other side Be treatment would be obvious for a lab test.

I bought many yellow sapphire Be treated and saw many nice gems with that typical color of the Be treated (like Barbra said). But from time to time you can come across very nice yellow sapphire Be treated with no clue. Here is 2 yellow sapphires the heart is Be treated, sorry picture is not very good, the stone is clean. The cushion is yellow sapphire, no treated. The price relation between those 2 stones is like 1/10, so I think it is very important for the lab to test the stone for Be treatment.

Oli.


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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 10:26 am 
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Microscopic evidence of heat treatment usually involves observing the alteration of inclusions within the corundum. The nature or absence of inclusions can pose a challenge.


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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 2:07 pm 
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This is probably a dumb question, but do be-treated stones have a very distinctive shift in color. My sapphire goes to a very violet color in incandescent light. It's more blue in natural light. Or is even something like this inconclusive?


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 Post subject: Re: AIGS ability to test for diffused corundum
PostPosted: Tue Jun 15, 2010 2:16 pm 
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with the flood of Be-treated stuffs a number of "weird" colors appeared, neverthless i don't think it's your case or it could be somewhat conclusive for your case.

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alberto

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