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Treated Emerald Uncovered

I recently had a customer bring me a Brazilian Emerald he bought recently to review/examine. From the very first look I noticed that the Crown Pavilion and Table Facets were a different color green ( much darker) than what was seen when viewed on it side looking at the girdle of the stone. As a matter of fact the entire center appeared blue to aquamarine greenish blue.When viewed under all spectrums of light and then with a Chelsea Filter I saw no red or signs of Chromium that can be indicated. NONE. So I believe the stone is actually not an emerald but rather a treated Greenish Blue Aquamarine which has added to it Opticon with a green pigmented Cedar Oil. Spectrometer testing also revealed treatment had been done.
I was upfront with my customer who now wants his money back from the person he bought the alleged emerald from. I hated to tell him my findings but felt morally obligated to divulge my findings as we both trusted the gem dealer and have bought from him in the past and the gemstone was fairly expensive for what it was.

I would welcome any thoughts or recommendations with regards how I handled this, any similar experiences with Brazilian purchased emeralds, my findings, my testing methods or any other testing methods that would also help prove my findings.

I live in Salvador/Bahia/Brasil since 1991 & have been dealing Brazilian gems since then. I’m familiar with Brazilian emeralds. Nobody serious would identify definitely any gem only based on fotos, but what I can see here as “inclusions” has nothing to do with emerald inclusions from Brasil or from any other origin nor with what we find in aquamarines. I use to call the type of “stone”, vidrolita & plastiquita.
Just my 2 cents

Looks like a doublet - a thin layer of natural emerald on a synthetic base.

Emerald doublet

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Could it be tourmaline? Both the Canadian Institute of Gemmology and AJS Gems referenced that in South America, where the majority of such gem - quality material is found, green tourmaline is still referred to as “Brazilian emerald”

I tested it and the RI / spectrometer and S.G. puts it at Beryl still.

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That is interesting! A bit more distinguishable banding than I’m seeing but it could be aquamarine in the center of the one I tested. I believe the one I looked at has Opticon mixed with a green pigment on the top crown and table and pavilion. Probably used to stabilize the surface cracks and make it look like a more valuable stone than it is. I don’t see any Chromium so I thinking the doublet would still show chromium right?

I agree with everything you just said! I was hoping that there might be a way to test for the Opticon epoxy and pigment. under 150X I see what appears to be dye or pigment as well!

That is interesting! A bit more distinguishable banding than I’m seeing but it could be aquamarine in the center of the one I tested. I believe the one I looked at has Opticon mixed with a green pigment on the top crown and table and pavilion. Probably used to stabilize the surface cracks and make it look like a more valuable stone than it is. I don’t see any Chromium so I thinking the doublet would still show chromium right?

If customer wants his money back he should send the stone to GIA for independent testing and, depending in results, have his lawyer send a letter of demand. If you’re also a buyer from the same dealer you probably don’t want to be involved in the dispute. Whatever the GIA results are will also help inform your own results and testing methods.

This is just additional commentary to your comments. Although getting a GIA Lab Report is a good step towards getting a buyer’s money back … I don’t see any lawyer running into court with it. A GIA Lab Report is not signed by anyone that can attest to its accuracy, therefore under the rules of evidence it is considered hearsay. Additionally as such, the GIA does not legally certify anyone or any thing. On the other hand, Lab Reports by the AGL lab are signed, so I would suggest using their report(s) if you need to go to court for relief.

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Now some observations and comments about this alleged treated emerald. My first impression is the color is off to be an emerald. Personally, I would check the RI on the pavilion facets and girdle to see if they match the RI’s taken on the crown facets. I further agree with jbergman’s observation that the stone appears to be a doublet. I feel that this stone was fabricated to appear to be a Paraiba Tourmaline. And lastly don’t forget that there is Green Beryl which is not Emerald. There is also colorless beryl which is called Goshenite. I hope this discussion is useful. :smiley:

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I agree with everything you said. I have basically said the same thing to my customer as well.

Hi all,

I found a really useful test that removed the dye and Opticon resin from a similar so called ‘ Brazilian Emerald ‘ . I just used a good old cotton bud and dipped in alcohol then rubbed it gently over the edge and it removed the green dye. I then went ahead and did the entire piece and it was pretty clear it was dyed.

It’s a very simple test but I would only do it on a raw piece that is unfinished so as not to damage the gem further.

Typically alcohol is a “no no” on an emerald. Just wondering is there a conclusive non destructive test specifically for Opticon?

Review this 1991 GIA article … the answer you seek is within. :smiley:

Everything You Want to Know About Opticon in Emeralds