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how common is heated spinel?

Arkteia

Arkteia

Ideal_Rock
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Nov 3, 2009
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I read that it happens these days. Today I spoke to a jeweler who showed me a spinel and admitted that it was likely heated. Given the fact that I have "allergy" to treated stones and try not to buy anything treated unless it goes with the territory should I certify each and every spinel I buy? Or stop buying it?
 
Unless heating affects a value of a stone eg Sapphire OR you are paying a high premium for an unheated stone and wish to verify that, I personally wouldn't bother with sending each and every stone to a Lab.

For me, heating isn't really a treatment per se. Heating occurs naturally in the ground and therefore if a stone is heated once it's been mined it's akin to just finishing the process that nature started - IF nothing else has been added to the mix.

Unless you are selling your gemstones at some point, or paying top $, then I'm not sure I would bother with getting a lab to verify everything. If you set the bar so high for yourself, you'll likely miss out on some gorgeous stones.

In terms of treatments to Spinels, they can be oiled, there's new evidence that some are being diffused and black spinel may even be coated! Here's a couple of articles on the heat treatment of spinels. I'm not sure if there is much of a price difference between unheated and heated spinel. If there is, I wouldn't think it would be much as these are more "collector" stones than one that Joe Public will rush into a jeweller and ask about.

http://www.gia.edu/research-resources/news-from-research/Heated%20spinel%20Identification%20at%20April%2002%202009.pdf

https://app.e2ma.net/app/view:CampaignPublic/id:1401417.6748130297/rid:de312d3b80688a5f860bd20eeb5ee1da#heat-treated-spinel
 
crasru said:
I read that it happens these days. Today I spoke to a jeweler who showed me a spinel and admitted that it was likely heated. Given the fact that I have "allergy" to treated stones and try not to buy anything treated unless it goes with the territory should I certify each and every spinel I buy? Or stop buying it?
Click to expand...

Heating of spinel is not common at all since heating does not improve the color. I've talked to some gem burners here in Thailand who've tried to heat spinel and they've told me that they only succeeded in ruining some good stones, so they no longer bother. As far as testing goes, I've sent hundreds of spinels to gem labs and have yet to have one come back as heated.

Your concern with spinel should be synthetic, not treated, stones.
 
Morecarats is correct, I have also talked to treaters here in Thailand about their experience with heating Spinel, very little improvement but more cracking so it generally is not done.
I like to see a few inclusions, besides fractures, in a Spinel so I know it is natural. There is a huge amount of synthetic Spinel in the market. I would advise you have a report made of identity only which will tell you natural or synthetic, would not waste money on finding out if it was heated or not. Best regards, Lee
 
morecarats said:
crasru said:
I read that it happens these days. Today I spoke to a jeweler who showed me a spinel and admitted that it was likely heated. Given the fact that I have "allergy" to treated stones and try not to buy anything treated unless it goes with the territory should I certify each and every spinel I buy? Or stop buying it?
Click to expand...

Heating of spinel is not common at all since heating does not improve the color. I've talked to some gem burners here in Thailand who've tried to heat spinel and they've told me that they only succeeded in ruining some good stones, so they no longer bother. As far as testing goes, I've sent hundreds of spinels to gem labs and have yet to have one come back as heated.

Your concern with spinel should be synthetic, not treated, stones.
Click to expand...

I agree, and I'm grateful that heating doesn't improve color. Synthetics are my big worry when it comes to spinel.

While I don't mind a heated paraiba, or some gems that are heated, heat treatment raises a red flag to me for other varieties of gems. I refuse to buy any more heated corundum, because heating may also mean diffusion or filler. For others, it may also mean irradiation came as a secondary treatment. While I can tolerate just heat, many of the secondary treatments are difficult, if not impossible to detect, and I just prefer staying with stones that are untreated as a result.
 
Interestingly, according to the studies by GIA, the spinel studied that had been heated doesn't appear to have improved the colour - only clarity.
 
tourmaline_lover said:
morecarats said:
crasru said:
I read that it happens these days. Today I spoke to a jeweler who showed me a spinel and admitted that it was likely heated. Given the fact that I have "allergy" to treated stones and try not to buy anything treated unless it goes with the territory should I certify each and every spinel I buy? Or stop buying it?
Click to expand...

Heating of spinel is not common at all since heating does not improve the color. I've talked to some gem burners here in Thailand who've tried to heat spinel and they've told me that they only succeeded in ruining some good stones, so they no longer bother. As far as testing goes, I've sent hundreds of spinels to gem labs and have yet to have one come back as heated.

Your concern with spinel should be synthetic, not treated, stones.
Click to expand...

I agree, and I'm grateful that heating doesn't improve color. Synthetics are my big worry when it comes to spinel.

While I don't mind a heated paraiba, or some gems that are heated, heat treatment raises a red flag to me for other varieties of gems. I refuse to buy any more heated corundum, because heating may also mean diffusion or filler. For others, it may also mean irradiation came as a secondary treatment. While I can tolerate just heat, many of the secondary treatments are difficult, if not impossible to detect, and I just prefer staying with stones that are untreated as a result.
Click to expand...


This is good to hear since I just bought my first spinel from Tan :D
.96 cts

spinel.png
 
Barry told me once that he tried heating a spinel....which just made it crack and did nothing to the color.
 
perhaps the person making the statement is uninformed re spinel and assumes that because other color stones are heat treated then spinel must also?

MoZo
 
Very interesting conversation! Maybe you should ask the guy how he's sure its been heated crasru. Everything I've ever read about spinel is that heating dosen't do much. The clarity maybe but if it screws up your color why bother? I would rather have a spinel with inclusions than a totally clean one that is caca for color.

Maybe buy it on the contingent of it being real after its been certed and not synthetic if it looks nice.


-A
 
LovingDiamonds said:
If there is, I wouldn't think it would be much as these are more "collector" stones than one that Joe Public will rush into a jeweller and ask about.

http://www.gia.edu/research-resources/news-from-research/Heated%20spinel%20Identification%20at%20April%2002%202009.pdf

https://app.e2ma.net/app/view:CampaignPublic/id:1401417.6748130297/rid:de312d3b80688a5f860bd20eeb5ee1da#heat-treated-spinel
Click to expand...

I would respectfully disagree on it. When I was reading my first book on gemstones (I was around 8), the author mentioned five "precious" stones: diamond, ruby, sapphire, emerald and "noble" spinel. By its chemical properties and color it is comparable to corundum so in my book it is a precious stone. The fact than general public does not know much about it (my best friend thought it was "a vegetable, something like asparagus" when I first mentioned it) does not mean that it is a collector stone, or shall remain such for a long time. In my personal view, a "collector" stone is something you can not mount so it has to lie in the box. Sphalerite is a collector stone, although some people manage to make jewelry out of it. Benitoite is a collector stone. And even hayune is (again, you can mount it but such jewelry is not for daily wear). Stones that are wearable on a daily basis are not "collector".

The reason I try to certify most things I buy unless they are very cheap and vendors are exceptionally well-known is simple. If I plan to mount anything and spend money on it I have to be sure that the stone is worth mounting. Even a pair of cheaper mountings from China cost something. I promised my friend a pair of "asparaguses"; I have to be true to my word because I am spending her money. If I bought something as spinel I have to be sure it is not synthetic. If I plan to set and wear it I have to be sure it was not treated. Otherwise it makes no sense because there is enough unheated spinel to mine.
 
And, Dave,

Your spinel is beautiful. If I bought such a spinel without spending much money on it and did not plan to spend much on setting, I'd not certify. If I invested something and planned to invest much more in a setting (Leon Mege gave me his quotas; case is closed as far as I am concerned but I have not spoken with other jewelers; anyhow, a beautiful setting is not cheap) I'd check. How much more can you spend on GIA cert? AGL? Much less than you would spend on a nice setting I presume.
 
And BTW - so that people do not understand me the wrong way - my question has as much to do with Tan as with any other spinel vendor. I have a lot of uncertified stones bought from our well-known vendors. And while I would not certify Bob Kast's stones because of their price, I will certify Eric's spinel because I got no certificate for it (although I strongly suspect it has not been processed in any way), or Gary's sapphire because it has no memo attached to it, or Jeff's chrysoberyl, although I believe it is natural. Some people sell at such a low price that I won't even bother; one well-known vendor I bought from once and shall never do it again although the stone he/she sold was totally natural (the description did not really match the color). The stone is not worth certifying, and the vendor is honest but my own experience was not positive. But too many stones have no certificates, although they are sold at a high price and vendors should have bothered to get at least AGL memo. Look at some websites - the stones are sold over 5K and vendors offer no memos? Tan always provides a memo if you ask him to; for expensive stones it is done automatically; the ones I might certify are the ones I plan to put into expensive settings.
 
Is this thread about heated spinel (which doesn't seem to actually exist really) or about you wanting to get lab reports on all of your stones?

For the record, very shortly I will be spending about $1,800 to set a stone that was $300. It is not certified in any way, shape or form. It will not be certified in any way, shape or form. Do I care? Not really. Neither the stone or the jewelry item is for investment purposes. I think it's beautiful and I think the setting I'm putting it in is ideal for it.
 
This is just a "by the way" type of comment: I think that Gary at finewater said that his mahenge rough was heated when I asked him about it (but ask him to be sure just in case I am misquoting him).
 
FrekeChild said:
Is this thread about heated spinel (which doesn't seem to actually exist really) or about you wanting to get lab reports on all of your stones?

For the record, very shortly I will be spending about $1,800 to set a stone that was $300. It is not certified in any way, shape or form. It will not be certified in any way, shape or form. Do I care? Not really. Neither the stone or the jewelry item is for investment purposes. I think it's beautiful and I think the setting I'm putting it in is ideal for it.
Click to expand...

It got sideways because some PS-ers were advising not to certify certain stones. I was just expressing my own opinion, Freke. I would not feel comfortable setting a heated stone in an expensive setting and later thinking I could have done better by buying unheated stone. And while stones are not for investment purposes, if I ever decide to resell, like many people do, on ebay, church bazaar or elsewhere, I absolutely need to be sure that I am selling exactly what I claim I am selling. It will be question of my integrity as a seller.

For the record, heated spinel exists. And while it may not be of relevance at this point in time, any new treatment may potentially lead to more serious treatments. Heated Paraibas are one thing, dye-infused tourmalines marketed as "Paraibas" are worth nothing. Hence we should be aware of such treatments. Otherwise we shall end up buying cheaper products at old, higher prices. Which, in a way, is poor investment of our hard-earned money.
 
Some stones like garnet and I think spinel arnt even disclosed as heated or not heated because it doesn't do anything to the value or is not a typical treatment. So there is no reason to tell a buyer heated or non heated.
 
I don't think you have much to worry about with heated spinels. Pretty much everything I have read to date leads me to believe that heating while slightly improving clarity also causes the color to be less appealing to most consumers. Not much profit in that for gem vendors.

Crasru, would you please tell us more about these dye infused tourmalines being sold as "paraiba"?
 
Heating is relatively new and not known to improve colour. In fact, I've seen the pictures of studies where the colour seemed to be poorer although the clarity is improved. I am not sure why and how your vendor knows the spinel has been heated as a fact. At this point, heating of spinels is not prevalent in the market.

Crasru,
Are you referring to the copper infused tourmalines being sold as paraibas or something else?
 
I hope I can post the link. I am not sure it is a forum. Let me ask Ella.
 
Does anyone know if they're diffusing spinel? I wouldn't put it past the treatment gurus. If they can find a way to alter a gemstone to a more valuable color, they'll find it.
 
TL,
I am sure they are trying as we are typing our posts. If there's a way, they will do it.
 
colormyworld said:
I don't think you have much to worry about with heated spinels. Pretty much everything I have read to date leads me to believe that heating while slightly improving clarity also causes the color to be less appealing to most consumers. Not much profit in that for gem vendors.

Crasru, would you please tell us more about these dye infused tourmalines being sold as "paraiba"?
Click to expand...

OK it is easy if you Google "dyefused tourmalines" you'll find all the websites. I sent an e-mail to Ella just for my own knowledge (I am not sure which websites are considered forums and which are not) but there are at least 10 different places on the I-net where you can read about it or see the photographs. Of interest, I found no info about it at Palagems. They are usually good at mentioning new treatments. If I understand it right part of the discussion is around marketing terms. Given the new technology, only Brazilian Paraibas can be marketed as "paraibas"; the rest of the stones should be marketed as "paraiba-like" tourmalines. And the dyefusion has to be disclosed.
 
Chrono said:
Heating is relatively new and not known to improve colour. In fact, I've seen the pictures of studies where the colour seemed to be poorer although the clarity is improved. I am not sure why and how your vendor knows the spinel has been heated as a fact. At this point, heating of spinels is not prevalent in the market.

Crasru,
Are you referring to the copper infused tourmalines being sold as paraibas or something else?
Click to expand...

The abundance of "paraibas" on the market; some of them are dyefused tourmalines.

TL - I am sure they are diffusing spinel right now while we are discussing it as a future possibility. It is plain scary.
 
RockHugger said:
Some stones like garnet and I think spinel arnt even disclosed as heated or not heated because it doesn't do anything to the value or is not a typical treatment. So there is no reason to tell a buyer heated or non heated.
Click to expand...

Each treatment has to be disclosed especially when the stone is sold as untreated. I do not know if it does anything to the value; future will show. Since at the moment there still are unheated spinels and unheated/unfilled garnets in the world, I'd prefer to buy them. If I am buying something else, I'd rather be told.
 
As for disclosing treatments. I am pretty sure it is only required if the treatment adversly effects the value. Blue topaz for instance is often not disclosed as irridated or heated.
 
colormyworld said:
Here is a link for some research the GIA has done on the subject of diffused tourmaline.

http://www.gia.edu/research-resources/news-from-research/copper-diffusion-tourmaline-update.pdf

I once saw an ebay vendor state that his spinel was diffused. Caused quite a stir. I am pretty sure it was a synthetic spinel not diffused. That is the only time I have even heard of such treatment to spinel.
Click to expand...

Colormyworld,

Thank you very much for posting the link. I don't understand why you needed me to do it but thanks anyhow. I can not load the pdf format but I presume it alludes to the same article. Apart from ebay vendors' statements, if they be and ti-treat sapphires, can you imagine similar treatment of spinel (using another metal/salt?)
 
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