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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Wed Apr 04, 2018 11:51 pm 
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Ah, so they did publish a full paper! I only found their abstract from a conference. That said, this is far more recent than the report, and the authors mention fluorescence as a possible method in their conclusions as well, which our own forums users have found to be a dead end in the past. Their sample size is also too low, at only 38 stones, and they don't seem to have controlled for origin beyond stating where their natural blues came from. These seem like pretty darned important potential confounding factors. Maybe Peretti did notice this difference before others (certainly possible since CL microscopy has been around quite a while) and assembled a big enough database of stones to be sure of its efficacy. In that case though, why would he need to examine the rough?

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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Thu Apr 05, 2018 3:06 pm 
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Bravo, once again Stephen.

If CL microscopy produced diagnostic results with topaz, it would stand to reason that others would have done subsequent study to confirm the original study.

And, furthermore, if GRS was able to reliably detect topaz treatment, I would suspect that the results would be well documented in their established library of breakthroughs.
http://gemresearch.ch/article-library/
GRS has a history of freely sharing industry information.

This is indeed a curious conundrum.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Thu Apr 05, 2018 7:02 pm 
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I really respect Dr. Peretti when it comes to ruby and sapphire (especially Pads) but I really don't like what his company is doing with this " untreated blue topaz". As far as the CL Spectra Microscopy is concerned- it's mostly Chinese to me (it was done at the China University of Geosciences). On page 18 of the study ,the chart mostly overlaps the characteristics of natural blue, natural colorless, and irradiated blue. Not a very strong case for natural blue in my eyes. So my final conclusion is that any blue topaz with any lab report is still just 5 buck a carat material.

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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Thu Apr 05, 2018 8:19 pm 
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I agree, Nicky....we still have no idea if CL was what was used to make a determination.
Could be as simple as the client saying "I found this pebble in 1965." and assumptions made on that fact alone.

We may never know.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Thu Apr 05, 2018 11:55 pm 
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Irradiated blue Topaz in all of its various colors and treatments is one of the most common stones sold in the jewelry industry these days. So, although the price per carat is low, the amount of money spent on this material annually is significant. I have personally been involved it treating millions of carats of this material starting in the late 1970s. I have never heard of a reliable way to be absolutely certain of natural color.

The GIA reports I have seen typically say something along the lines of : "The color of blue topaz is often the result of irradiation, and heating. Evidence to confirm irradiation and heating are typically lacking"

I am surprised to hear of a well known lab stating no treatment/natural color. If it is possible to prove treatment, sharing of the technology would be a valuable contribution to the industry.

I am hoping to learn more....


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Sat Apr 14, 2018 4:05 am 
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Sorry, I had missed this discussion's revival.

Ricardo, I have been asking from the day I saw your stone to get Dr. P. to tell you as the owner and fee-payer where his magic is.

As a company, we have 'fought over' thousands of no-treatment-reports in all varieties and with all labs over the last 15 years. If it were my stone and my fee I would bloody well insists on being well informed for my $$$$-report.

Not doing this, Ricardo, or delaying, only decreases the potential value of your gem. If you had Dr. P.'s explanation in hand, you would hold a world-wonder super-topaz and ask any price you like. Without it, all you get is doubt.

It is also wishful thinking that a buyer would pay a no-treatment premium, and then go ask Dr. P. for an explanation. Nobody will take that risk. In today's well informed collector circles, people know about the treatment-issue in topaz. If you'd find a buyer who doesn't and can't use google, I'd not want to profit from such a sale. Bad karma.

If there is no 'secret magic' at GRS, I would want my money back and a public 'mea culpa'.

Plus all the hours you (and some myself) have invested. It would be a shame if GRS gets away with still earning a fee!! Bad for the whole industry.

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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Mon Apr 16, 2018 11:18 pm 
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So the report states that the rough was examined for the determination of it being natural. Is there any identifying characteristics present in the rough like inlusions that may alter from heating. I am concerned as I am ready to cut a 1000 carat piece from Brazil that I bought in Tucson as natural from a trusted source.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Mon Apr 16, 2018 11:33 pm 
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No. The heat treatment is done at a relatively low temperature, and for removing brown tones from blue topaz you can probably get the same result from just leaving it in the sun for a little while.

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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Tue Apr 17, 2018 1:01 pm 
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A lot depends on how you want to roll with the stone defined as natural without evidence of treatment.

It is natural.....not synthetic.
No evidence of treatment because after blue topaz is Irradiated and annealed to stabilize the color, there will never be any evidence of that treatment.

Saturation is the best clue to suspect treatment as almost ALL topaz found in nature is close to colorless with the slightest tinge of blue.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Tue Apr 17, 2018 6:12 pm 
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I know you guys are not advocating it, but based on the above, the following would be technically correct, but misleading.

Natural Topaz
50ct
Oval Brilliant Cut
Dark very slightly Greenish Blue
No evidence of treatment

The FTC has a stricter requirement for disclosure. When treatment is common, likely, or suspected, even though it cannot be proven by residual evidence it is prudent to disclose a streated.

When it is not known with certainty whether or not a gemstone has been treated, but treatment is suspected
(as in the case of gemstone types which are known to be routinely treated), the FTC states that “it is prudent and
appropriate to disclose gemstone treatments rather than remain silent when there is a possibility that the stones
have been treated.”


The AGTA is even more strict.

Since many enhancements are difficult or impractical to prove definitively, the approach taken in this
manual is, unless otherwise indicated, to assume that such traditional enhancement has been done to
that particular gemstone. This assumption has been made in order to protect both the seller and the
consumer.


So almost all deeply colored natural blue topaz should have both the "N" and "R" treatment designators.

It should also be noted that the disclosure requirements apply to rough as well as cut stones.

So the cert in question is actually technically correct in the same way as my example. Even the rough would have "no evidence of treatment". The owner is said to be representing that this cert means the stone is untreated. In the U.S. the lack of the two treatment designators would seem to back that up, because the cert would not be compliant with FTC, or AGTA rules. Since GRS has offices, and issues certs in the U.S. they should be required to conform at least the FTC standard disclosure.

So, does FTC requirement apply to gem labs issuing reports, or only to transaction involving the sale of goods?

The legal meaning of this cert is still in question to me. It implies no treatment, but is still tecnically correct even for a treated stone.

I am too complicated, I know...... :roll:


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Tue Apr 17, 2018 8:22 pm 
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No, Steve, you are 100% correct.

This whole situation seems very odd to me. Dr. Peretti is really top of his game.
There must be more to the story. I hope there is more to the story.

And by the by, grading and identification reports are not "certificates". Legally the term certificate implies a warranty. If we read the disclaimers on the back of lab reports, we will learn that a lab guarantees nothing. They simply offer an educated opinion within the limitations of their knowledge, experience and instrumentation.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Tue Apr 17, 2018 9:43 pm 
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Thanks for pointing that out, as I have done too many times myself to others. Report is the proper term. I used "Cert" because that is what the current owner called the document in his post on this thread. I didn't want to confuse the issue with the meaning of "no evidence". When I wrote generically about labs, I did use "report" which is my habit.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Thu Apr 19, 2018 9:20 am 
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So what is relatively low temperature for heating topaz. I have damaged my share of gems At temperatures under 1000 degrees Fahrenheit . Not to mention what may have occurred at lower temperatures which may not be obvious to the eye. . As far as sunlight treatment who waits when you can heat in hours. Seems like it would be worth looking into as it seems there is no other means of detection and heat can be so destructive particularly in the rough where there is a variety of inclusions.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Thu Apr 19, 2018 3:09 pm 
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The blue color of topaz is the result of bombardment by gamma radiation and subsequent annealing at temperatures 200-300º C.


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 Post subject: Re: GRS report for 'untreated blue topaz'
PostPosted: Thu Apr 19, 2018 4:58 pm 
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200-300 c is very mild, and unlikely to do anything diagnostic. Sunlight would likely work in a few hours depending on the day and the stone.

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