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 Post subject: EXA
PostPosted: Fri Jun 18, 2021 10:38 pm 
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Hi I have a EXA Natural Diamond Detector that I use in my lab. My boss doesn't really know a lot about it but I am trying to become proficient in it but have no peers to talk to. Today I had a client come in with a 5 carat (according to IGI) mounted diamond and it failed the pass or refer test, and also was glowing green when I placed the probe to it. The stone was graded J/si by IGI but since I didn't get the pass I told them they must send it to GIA to evaluate further, I looked at it under the scope and did see a natural on the girdle but I just felt they should send it to GIA. I looked at the spectrum and it was lining up with type IIA (yellow) and IRR green diamond. I just felt suspicion that maybe it was treated. The clients were naturally upset even though I tried to explain it didn't mean it was lab grown but rather I couldn't tell. anywaay this ordeal is bothering me a great deal.

Can the EXA detect color enhancement with HPHT? wouldn't it be inscribed?

Thanks


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 Post subject: Re: EXA
PostPosted: Sat Jun 19, 2021 12:03 pm 
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Location: San Francisco
Good Morning Loupegirl and welcome to GO.
I too have an EXA and I have found it extremely reliable.

Under the circumstances you explain, I would say that your results are simply inconclusive. I would recommend that the client take the diamond back to the seller and make the sale contingent on providing a GIA report.

If this isn't possible, as the client has owned the diamond for a long time, arrange for a 2nd report with GIA.
I presume you have verified the IGI report:
https://www.igi.org/reports/verify-your-report

Sidebar: Why would anyone buy a 5ct diamond without a GIA or AGS report is baffling.


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 Post subject: Re: EXA
PostPosted: Sat Jun 19, 2021 6:57 pm 
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Do not let how the client feels bother you. That would be like a Doctor not telling the patient unpleasant test results. The consequences of not telling are worse than the unpleasantness of telling.

The EXA Natural Diamond Detector is a first class piece of equipment. Trust your instrument. This is a fairly easy test to do so operator error is unlikely.

Just explain it to your clients as clearly as possible:

The EXA Natural Diamond Detector is a well respected instrument and its results are considered reliable.

It will properly identify 98% of natural diamonds.

2% of the time a natural diamond will have an inconclusive result. Basically it is the same result a lab grown diamond would get. Unfortunately, it appears that your stone falls into this 2%.

The recommended procedure for when this happens is to refer the stone out to one of the major gem labs for more advanced testing that can differentiate between lab grown and a very rare type of natural diamond. You should look at this like a patient being referred out to a specialist by his general practitioner.


If your client doesn't accept that kind of answer that is on them not you. You can rest easy knowing you did the right thing gemological, and ethically.

Just like medicine, technology in treatments and synthetics has advanced a great deal in recent decades. It used to be that the G.G. was the authority. Now a G.G. must view himself like a General Practitioner Doctor. They can handle the vast majority of cases/stones that are presented to them. But a certain percentage will need to be referred out to a Specialist with advanced equipment and training. Knowing when to make such a referral is as valuable to your client as an I.D..


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 Post subject: Re: EXA
PostPosted: Sat Jun 19, 2021 9:23 pm 
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Good answer, Steve!

If it was a recent purchase, I would still go back to the seller and insist on a GIA report on their nickel.


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 Post subject: Re: EXA
PostPosted: Sun Jun 20, 2021 4:09 am 
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I nominate Steve's answer as a candidate for the (non-existent) answer of the year award. =D>


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 Post subject: Re: EXA
PostPosted: Sun Jun 20, 2021 9:40 am 
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@Brian: i'll happily support the candidate with my vote :D


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 Post subject: Re: EXA
PostPosted: Mon Jun 21, 2021 3:12 pm 
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The situation was strange, originally they came to me with another stone and it was a moissanite, then even though I told them some reputable local jewelers they chose to order online. It was a delicate situation as the ring was for someone who was terminally ill. So they did not want to take the extra time to have the supplier send the item to GIA or AGS. That made the situation harder to handle as well. But I did not want to go further into the evaluation until they sent it because of the way the machine responded.

Next time I will be sure to word the results as "inconclusive" and also not to feel bad for doing my job to the best of my ability. I love the EXA and it has been really helpful so far, ironically I find it really helpful with colored stones.


Thank you all.


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 Post subject: Re: EXA
PostPosted: Mon Jun 21, 2021 7:46 pm 
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You did the right thing, LoupeGirl. Handled it brilliantly.

Sounds like they may have been up to no good. I'm so glad you didn't get involved in something possibly nefarious. We have our instruments to thank and the good sense to listen to what they are telling us.

I agree the "advanced" option on the EXA is the bomb. Use it all the time as well.


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 Post subject: Re: EXA
PostPosted: Wed Sep 22, 2021 4:11 am 
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Hi Loupegirl and sorry for finding your post too late...
do you have the last version of the EXA manual? there are some natural diamonds not featuring the N3 snd hence not getting a pass, that can be still identified as natural by using the advance mode. They are typically IaA with a lot of H3 defect causing a glowing yellow-green fluorescence AND the A aggregates quenching the N3 reaction do not help the spectrometer in identifying them as natural by the Pass/refer mode...anyway, if you happen to have saved an image of the spectrum I would be glad to drop an eye to it...........

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GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


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