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 Post subject: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIRE."
PostPosted: Tue Sep 04, 2012 12:01 pm 
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Just received some spam from a dealer in the Hong Kong jewellery show offering:

"Sapphire Diffusion Treated created from natural scrap."

I give the seller some credit for disclosing "re-created", whatever that may mean.

The reason I'm interested in this is because I believe natural white sapphires are relatively rare (and clean natural whites are very rare) and that diffusion treated blue sapphires are relatively common.

So, I suspect a lot of the diffusion treated "blue sapphires" are actually diffusion treated synthetic sapphires that are difficult to identify as synthetic for two reasons:
--diffused color may obscure indications of synthetic origin and
--because someone testing the stone may be looking for diffusion without questioning the origin of the raw material that's been diffused, acting on the assumption that if it's been diffused, it must have been natural white sapphire to begin with.


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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Tue Sep 04, 2012 2:34 pm 
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I don't think natural white sapphire (Or synthetic white sapphire) turns blue with diffusion.

Ted Themelis published a study a few years back in the Journal of Gemmology where he diffused numerous white sapphires. Mostly they turned a very pale brown.


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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Tue Sep 04, 2012 11:56 pm 
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Just to clarify my initial post: I should have indicated I was talking about titanium diffusion.

I believe titanium diffusion will add blue to colorless sapphire.


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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Wed Sep 05, 2012 3:39 am 
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Hi Bill

billkent wrote:
So, I suspect a lot of the diffusion treated "blue sapphires" are actually diffusion treated synthetic sapphires that are difficult to identify as synthetic for two reasons:
--diffused color may obscure indications of synthetic origin and
--because someone testing the stone may be looking for diffusion without questioning the origin of the raw material that's been diffused, acting on the assumption that if it's been diffused, it must have been natural white sapphire to begin with.


everything is possible BUT, remember there must be always an economic reason behind if we 're talking large scale.......
so, surface diffused synthetic sapphire (i suppoese you're talking about flame fusion, right?), let's explore this issue a bit:

surface diffusion can be easily ID, no need for fancy instruments, almost always a loupe, a little lamp and a kleenex are enough.
Synth flame fusion are very often (almost always) inclusion free besides gas bubbles and curved striae which can be easily spotted even if the stone is surface diffused (thickness of the colored layer is actually very thin and doesn't help much to hide something inside).
Almost colorless or pale or patchy colored nat sapph crap are really cheap, perfectly suitable for surface diffusion, they share same internal features of the nice stones.

that said, i guess it's possible to submit a synth flame fusion to surface diffusion but......WHY? :wink:

ciao
alberto

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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Wed Sep 05, 2012 6:32 am 
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I have also heard of these surface diffused Sapphires. I have never seen one, but a reputable dealer in Chanthaburi told me that some people around the market take a lighter blue synth Sapphire, heat it to "Straighten out" the straie, then diffuse it to make it a more saturated blue.

This is just speculation, but I feel that sometimes the guys closest to the action should be listened to.

Just my opinion :D


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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Wed Sep 05, 2012 7:10 am 
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TreasureGems wrote:
I have also heard of these surface diffused Sapphires.


quite old treatment and, unusual for gemstone tratment, patented: have a look HERE

Quote:
I have never seen one, but a reputable dealer in Chanthaburi told me that some people around the market take a lighter blue synth Sapphire, heat it to "Straighten out" the straie, then diffuse it to make it a more saturated blue.

This is just speculation, but I feel that sometimes the guys closest to the action should be listened to.


yeah, neverthless if i get 1 cent for every rumor coming from there i would be rich... :wink:

ciao
alberto

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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Wed Sep 05, 2012 12:36 pm 
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three points:
--i've never seen an abundance of white/light/ottu sapphire in larger sizes that was nearly as cheap as synthetic flame fusion.
--synthetic white sapphire isn't always easy to identify.
--economic motive: diffuse synthetic white sapphire that costs pennies per carat and sell it as diffused blue natural sapphire for dollars per carat.

just my opinion


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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Wed Sep 05, 2012 12:52 pm 
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ok then, if you find some, drop us a note. i for one would be really interested in having a sample for my collection. :D

ciao
alberto

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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Wed Sep 05, 2012 1:23 pm 
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in some areas, i have very little experience: diffusion corundum is one of those areas.

my entire inventory is unburned; everything is certed before i hand over the money so no one even wastes time by offering diffused.

now i'm being called upon to provide appraisals for someone else's goods and so i have to get up to speed on what's been fed into the normal jewellery channels.

so i'm trying to connect some dots--the main puzzle for me is that i've never seen big quantities of white/light natural corundum in sri lanka and yet there seems to be a lot of blue diffused sapphire in tv land and online.

i wish to thank everyone here and especially barbara for making this knowledge-channel available to me--i greatly appreciate it! and i appreciate your rigorous scientific approach. thanks again!

bill


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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Thu Sep 06, 2012 2:57 am 
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TreasureGems wrote:
I have also heard of these surface diffused Sapphires. I have never seen one, but a reputable dealer in Chanthaburi told me that some people around the market take a lighter blue synth Sapphire, heat it to "Straighten out" the straie, then diffuse it to make it a more saturated blue.

This is just speculation, but I feel that sometimes the guys closest to the action should be listened to.

Just my opinion :D

i have seen these kind of syn Flame Fusion diffused sapphires too, actually it was a very big parcel of them (1500 catats in all shapes) and the seller (as he's been told) said they are natural diffused sapphires, detecting the diffusion was very easy but after observing the parcel i noticed they are extremely clean and with magnification i could ID some gas bubbles in some of the stones, i also find it odd to diffuse synthetics because they can add Fe+Ti and make blue sapphire why the trouble of diffusion? so i gave it some thought and find some reason to do it:
1- Syn Colorless Flame Fusion Sapphires are much cheaper than colorless natural ottu or light color sapphires
2- the color result of syn sapphires by diffusion is like typical Royal Blue which can be find in natural diffusions but they are much cheaper
3- they sell the product as Treated and not Synthetic!
4- vivid blue color of syn flame fusion sapphires are very obvious and not pleasant as the diffusion ones
5- synthetic flame fusion blue sapphire have color banding and detectable but in diffused color less syn sapphires you dont see any typical banding
6- because the industrial use of syn FF colorless sapphires they are cheaper than synthetic FF blue sapphires
7- all of the trouble is to make more money and it seems diffusion treatment cost worth to sell the product as natural diffused sapphires!

here is some tips to detect them:
A- Cut:
according to my observation of the big parcel of diffused created sapphires these sapphires have very poor cutting, Misshapen and Extra facets also Facets that fail to point properly are all indication of using cheap labor on cutting the cheap materials also Surface of these stones has a tiny wavy hairline like cracks
B- Clarity:
almost all of these materials have very high clarity grade
C- Magnification
minute gas bubble are detectable (immersion and proper lighting can help)
D- Price:
they are much cheaper than natural diffused sapphires and can be find in bulk and big parcels
E- Color:
most of them have deep to vivid violetish blue color (typical diffused royal blue color)

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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Thu Sep 06, 2012 6:49 am 
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Hmm....gained a lot from this interesting interaction! One thing that I know for sure.....colorless sapphire (leukosapphire) is not that rare as such natural colorless, or whitish sapphires are often offered by jewelers as cheaper alternatives to diamonds in jewelry designing....This is quite common in Asian markets, but I am not sure it is common or not in American and European markets.


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 Post subject: Re: "Diffusion Treated RE-CREATED Blue, yellow,pink SAPPHIR
PostPosted: Mon Sep 15, 2014 7:21 am 
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Part of this article from GIA is about Synthetic Diffused Sapphires

http://www.gia.edu/gia-news-research-Sa ... Synthetics

identification of the Diffusion treatment is quite straightforward, but determination of natural or synthetic origin remains a challenge. it even becomes more challenging to correctly differentiate between natural and synthetic when its been set in a jewelry piece.

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