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 Post subject: Heat Diffused Cobalt Blue Spinel?
PostPosted: Fri Apr 11, 2008 10:42 pm 
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Check out the very last item in the description of THIS ebay auction.

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 Post subject: Re: Heat Diffused Cobalt Blue Spinel?
PostPosted: Fri Apr 11, 2008 11:17 pm 
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brimsjewelry wrote:
Check out the very last item in the description of THIS ebay auction.


That's the first documented evidence I've seen of any spinel treatment other than oiling. Good catch.

"I've never met a gherkin I didn't relish."

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 Post subject: Re: Heat Diffused Cobalt Blue Spinel?
PostPosted: Fri Apr 11, 2008 11:47 pm 
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ROM wrote:
"I've never met a gherkin I didn't relish."


How sweet it is! hehe

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PostPosted: Sat Apr 12, 2008 1:01 am 
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very nice, now we have to see what "heat diffused" means.. ??

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PostPosted: Sat Apr 12, 2008 12:37 pm 
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I too would like to know what "Ceylon heat diffused" means. I would also like to know how the GIA graduate that determined the treatment qualifies that determination.

Heat treatment implies the use of elevated temperatures to alter or improve the color and or clarity of a gemstone.
Diffusion implies the use of heat along with chemical additives to alter or improve the color of a gemstone and the possible alteration of clarity characteristics as a consequence of the heating temperature needed to diffuse the chemical elements into the stone.
Ceylon is simply the former name of an island (Sri Lanka) off the southern SE tip of India best known for its sapphire deposits.
Of the tools used to determine treatment, listed on the linked page, which one could determine (with certainty) diffusion treatment?
Is the "Spectracope" a new fangled device for determining diffusion treatments ? No immersion device used for detection of surface diffusion?

I try to keep up on the latest happenings with gem treatments, but "Ceylon heat diffusion" is one I've never seen mentioned in Gemological publishing's as an individually defined type of treatment detectable with the list of instruments used in conjunction with this determination. And never mentioned in part or it's entirety as a detectable treatment of spinel.

Can someone bring me up to speed?


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PostPosted: Sat Apr 12, 2008 2:22 pm 
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I think we'd all like to know what this means JB. Until we can learn more, I merely take it as tacit admission that some sort of "cookery" is taking place.

I had a personal communication some time back from a Sri Lankan gem merchant/friend who said he was doing a study on possible spinel treatments. He's definitely in a position to know about such things. I've heard no more but will post anything relevant if I do.

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PostPosted: Sat Apr 12, 2008 2:48 pm 
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I emailed the seller and this was his response:
Quote:
Sure thing,
The listing actually list that incorrectly. I do apologize.

1. The Stone is Not diffusion treated. (I do apologize, the listing incorrectly states it is diffused)

2. It has been heated.

3. Per my GIA Graduate Gemolosigt: "Many tools are used or can be used to determine "Diffusion" treatment. Some are a Spectrascope, a Microscope, Real Light, Immersion, but you do not need to always immerse a gemstone to detect if it is diffusion treated. This stone is not Diffusion treated"

4. Correct, Ceylon is the Gemstone Origin.


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PostPosted: Sun Apr 13, 2008 1:12 am 
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Hi Barabara, this is the Seller. My name is David. dbaurjr on ebay

I thought I would share more on this"Diffused" I had mistakenly put on my listing.

First off, I am not a Gemologist, but I am learning, reading, and I have a GIA Graduate Gemologist that grades my items, he has been doing it 40 years, so I though I would share what he has told me, as I have had him check this stone, and check with GIA, and then recheck it again.

The first question I had was "Is it Heat Diffused" - His answer is that "Heat Diffused is when they use Beryllium diffusion, and can only be done to corundum (i.e. Only Ruby and Sapphire). It cannot be done to Spinel, nor has anyone ever produced a "Heat Diffused Spinel"
(If you search for Diffused Spinel on Ebay, quite a few show up shockingly) but according to GIA and my GIA G.G. it is due to sellers not knowing what they actually have.

I have bought more than 90 Gemstones in the last 2 months on Ebay, and I have a deal with my GIA G.G. to check them for a reduced cost, and ones that apprise for over 1,000 I get a Full GIA G.G. Appraisal on. The thing I have found out so far is that about 64% of the items I have gotten were incorrect in their listings, as they relied on their wholesalers to tell them what it is....and apparrently they don't have a real clue some times.

Anyway, I started buying and selling because I was basicallyu ticked that so make syntehtics, filled, doublet, triplet, glass, CZ where beign sold as real. So I have everything checked. If you see feedback I have left for others, it really cracks down on them. Ebay has gotten rid of like 4 Sellers due to my actions and doing this, so I am actually cleaning up ebay it feels like, however slowly from people selling fakes/syntehtics,etc.

He spent 4 hours doing various test to make sure this was real, I know as I sat there trying to stay awake. The most fascinating "Tell" though was his UV Long Wave and UV Short Wave Test, which were considered to be the ultimate tell with a Spinel, in this case we were testing for "Cobalt Blue Spinel" The readings matched the GIA specifications across the board. That being the Spinel shows as a Red under L/W and beleive it or not it looks like white chalk with a green tint under S/W...So this was neat to see.

He used every tool he had except for Emmersion, which is really nasty stuff, very toxic. I asked why not when Immersion tells if something is synthetic, and he said because you only do that if any of your other test make it suspect, which they didn't. He then spoke with his contacts at GIA, and they said "No such thing as Diffused Spinel, but would check to see if anything new has creeped up, but they would have remembered seeing something that Dramatic"

Now guess why I did so much concerning this Gemstone?
In a short answer, the seller said they could sell me 14 more for $210.

When I posed this to my GIA G.G. he then understood my concern, but then asked if the seller was in Asia, Sri Lanka area, and he said well they do come from near to that area in Ceylon, so not to worry. So I did have him do the "Certificate of Appraisal" as well. He said it is the best he has ever seen in his 40 years, and to tell you the truth, the pictures are nice, but in real life seeing it is really just awesome.

I anybody has any questions or anything let me know please. Take care!

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PostPosted: Sun Apr 13, 2008 12:29 pm 
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Hi debaur,

Is there any chance that your U.S. based Gemologist would share with us his technique for identifying heat treated spinel? There are no references for this determination in the GIA lab manuals. Just says no known treatments.

Is he using microscopic inclusion characteristics for this identification or other methods?

Thanks.


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PostPosted: Sun Apr 13, 2008 2:36 pm 
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Standard diffusion is not done on Spinel; there was no sign of heat treat either though.
Testing for “Diffusion”
Use the standard diffusion process. There are two kinds surface (only color changes the surface) or beryllium (which drives color into the stone using very high heat). In testing for diffusion, it means heat treat plays a part as well in beryllium, so seeing broken silt would also be a sign that it may be diffused as well.
You find out by just using standardized gemological test.
1. The primary test is to use diffused back light with magnification, and then if it shows signs of diffusion you would go to the second test
2. If you find evidence of diffusion ion # 1 above (which you should only use it there were signs or immersion) using metholine iodide as it is most effective, but very toxic.
Surface Diffusion:
On a surface diffused stone, turned it face down, with back diffused light, the concentration of color will be on the edges. If test is no diagnostic, then got to next test (immersion)

JB, I sent you a PM with his Contact info.

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PostPosted: Sun Apr 13, 2008 2:57 pm 
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Welcome to the forum, David, and thanks for clearing up some questions. I hope you will become an active forum member and share you stories of your quest to clean up eBay, which is long over due, and you have many kindred spirits already on this forum in that regard. Again, welcome. :D

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PostPosted: Sun Apr 13, 2008 4:40 pm 
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Thanks David,

I was trying to decipher what was on the original report in regards to treatments and what if anything was done to the stone in those regards.

As it turns out, it seems the report should say:

Treatments: None.


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PostPosted: Mon Apr 14, 2008 11:12 am 
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That fluorescence is a wee bit worrisome. Did you say there are natural inclusions?

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PostPosted: Mon Apr 14, 2008 11:40 am 
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Richard,
I know what you are saying. Curiously enough, I have a FF syn spinel, dark blue, that shows neither the expected fluorescence of natural or synthetic blue spinel.

It definitely shows the typical cobalt absorption spectra for FF synthetic spinel. Maybe a better indicator than fluorescence.

I don't want to question the expertise of David's Gemologist, but something just isn't sitting right about this.


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PostPosted: Thu Apr 17, 2008 1:57 pm 
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Well, he has Called GIA and they said there are Diffused Syntehtic Spinel, and possibly now able to diffuse a Natural Spinel. They stated the GIA Colored Stones manual is incorrect. I have several more (ABOUT 5) "Suspect" Blue Spinel I have bought that state "Heat Diffused Spinel" .GIA has given him some new test to run, and I am going to send it to GIA and see what the Lab Report shows as well.
The complaint from my G.G. that he gave to GIA was "I cannopt call GIA every time I have a suspect Gemstone and the Guidance for Testing in the book be wrong".
As for me, I am so sick of seeing "Heat Diffused for Color Enhancement". So, we will get to the bottom of this. The sellers don't know or have not clarified it when I have asked them too.

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