Detection of Heat Treatment for Spinel

[smitcompton]

Hi All,

I just read and scanned an article on heat treatment for Spinel from the GIA Bankok and New york--2009 labs.. A Ramen devise can detect it and the test that TL uses for sapphires Ilap...

Apparently this came up, somehow at the Tucson Show, that Spinels were being heat treated. I know many of you would be interested, so I hope Administration won't delete my post as this article can be found on the website that cannot be named. It falls under the Synthetics and Treatment category and I know some of you will find it interesting. I would like your opinions.


Thanks,
Annette

I think we are getting less and less information out of the Tucson Shows each yr on this site. Vendors and gem collectors used to come n and talk about prices, scarcity of some gems and what seemed popular this year. I wish we had more info. Maybe we have to send our own rep. to the next show.

 

[Treenbean]

Re: Dection of Heat Treatment for Spinel

Thanks for the info. I will look up the article. I think things have changed here too, I can especially tell when I go on Rocky Talky. I think it's a great idea to send a rep. I vote Chrono or TL or Pandora. We could all donate. If we do it, we should start early with contributions so we have enough money to send the rep.

 

[Pandora II]

LOL - I'm in the UK so could be pricey!

OTOH lots of people I know do go so I can always ask them. Will see what I can find out on detecting TE in spinel.

 

[T L]

I heard that they were coming up with favorable heating results in Burmese stones, but not from other locales. It's a matter of time before spinels are regularly heat treated I would imagine. I just hope diffusion isn't next.

 

[JewelFreak]

Sorry to be a dunce, but why would attendees not be sharing info here as previously? Is it us? Or the price & difficulty of finding good quality -- in other words, less to report except that? Something must have flown right by my noggin.

Sad news about spinel; not unexpected, sigh. Thanks for the article, Annette.

--- Laurie

 

[minousbijoux]

I, like JF, am a bit confused. I thought spinels did not respond to heat treating which is why they haven't historically been heated? Is there a different chemical composition with the Burmese stones (which in general are my favorites)?

 

[LD]

One of the things I like to do is to look at the declaration of treatments on the GemsTV website in the UK. Interestingly, this usually has quite up to date information. About spinels it says that "rarely" they can be "impregnated with colourless filler to improve appearance" and they can also be lasered. Even though this has been listed as a rare treatment, it's safe to assume that they have knowledge of this otherwise it wouldn't have been disclosed.

With that in mind, heating shouldn't be a surprise.

 

[Imdanny]

My opinion is it should be a criminal offense.

 

[Dioptase]

Yeah it's not new, it has been going on on a small scale since 2/3 years. Most of the spinels don't react well to heat treatment but some do.
Thankfully, labs are able to detect the treqtment without any major problem.
The new scary thing in the trade is the irradiation of emeralds now.

As for foreign substance filling; one should be wary with EVERY stone. Absolutely everything with surface-reaching cracks can be treated that way with oil, various resins and so on. Spinel is no exception.

NB: A lot of tourmalines are filled with opticon or similar polymers, be careful.

 

[VapidLapid]

 

[smitcompton]

Hi,

I'm glad some of you looked at the article. I'll recap some of my understanding of the article.
1. If spinels are high heated they do not improve color, but darken it.
2.The sleepy spinels benefit the most from lower heat tetment and showed less inclusions.
3. Spinels from all locales were included in the testing.
4The tests were done by very reputable persons and the batch that wwas tested over-whelmingly show heat treatment.

JF-- Your question is a good one. If this info has been out there for 2-3 yrs, why is it no one of the vendors that are recommended on this board has mentioned it? My thoughts are they don't want to lose sales or do the extra work to see if their stones are natural.
Of course they may also be unaware of this, but hey this is their business and they should be up on the info.

Minoux--This board used to have more education from experts, big collectors, and vendors alike in the past. Its wasn't as much of a sales venue as it has turned out to be. You make vendors into rock stars here. TL, LD Pandoraq, MZ, Vapid Lapid I am in no way minimizing your contributions,

I, like LD watch JTV. I don't buy, but I get more info from them on Tucson than anywhere. Of course they make all gems scarce, but I sometimes learn something.

I also learned recently that Russian Demantoid is also heat treated. I think it was mentioned on here but what I am gathering is that it is a good part of the parcels that are sold.

JF-- Tucson is the largest colored stone show in the world. It is a wholesle show, I think. The diamond board gives prices , the colored stone board wants some as well, at least I do. The place to find them is Tucson.

It would be nice to have someone in Tuscon. I would be willing to contribute. I'd also like to suggest LD and Pandora can come for a visit to America. From Tucson, on to Las Vegas, San Francisco, New Orleans etc. Oh I forgot the Grand Canyon.

Well, I was upset with this news, not because it couldn't happen, but more because no-one has mentioned it. Thanks all for your comments.

Annette

 

[T L]

Yeah it's not new, it has been going on on a small scale since 2/3 years. Most of the spinels don't react well to heat treatment but some do.
Thankfully, labs are able to detect the treqtment without any major problem.
The new scary thing in the trade is the irradiation of emeralds now.

As for foreign substance filling; one should be wary with EVERY stone. Absolutely everything with surface-reaching cracks can be treated that way with oil, various resins and so on. Spinel is no exception.

NB: A lot of tourmalines are filled with opticon or similar polymers, be careful.

Non detectable irradiation is an issue as well, especially with tourmaline.

 

[chrono]

Annette,

Thank you for the heads-up for the spinel heating article. Yes, there was news brought to the PS attention several years ago about various treatment to spinels, namely heating. These do not make the sticky news. There has also been news on non-detectible irradiation of tourmalines, coloured fillers and oiling of certain types of tourmalines and also filling of garnets, heating of Russian demantoids and etc. In general, I see that it is the PS consumers and collectors who bring everyone else on the board up to date on the latest gemstone treatment. Perhaps the vendors are too busy to be a regular presence. This site is first and foremost, a consumer website, thus that could be the reason we don't hear much from the experts?

 

[LD]

Annette - I think there was a thread about spinels and heat treatment a year or so ago. I remember we had a long debate and there were some great examples of heated Spinels in it too.

BTW I don't watch JTV (I'm in the UK and they don't have that here). I occasionally watch GemsTV in the UK as it's interesting to see what they are selling and the price points! They are very good at declaring treatments and basically tell everybody that it should be assumed that each piece has been treated in some way.

 

[PrecisionGem]

Much of the Tucson shows that would be of interest to people here are closed to the public, you need to be a member of the trade. Certain seminars where this type of new information comes from are also closed to the public. The shows span several weeks, and even if you were a trade member (and they really check, you need to prove it, you won't get in just showing a business card), you would end up staying in town for 2 weeks to absorb everything. The hotels jack up the prices for the show, so it gets pretty expensive.

To really get a feel for prices is not the task for a single person. There are just too many shows and dealers, and everyone has stones that are older stock, newer stock, some people really want to move their goods, others will hang on for their asking price. Colored stones are a lot more complicated than diamonds.

 

[Pandora II]

Ditto this.

 

[smitcompton]

Hi,

Thanks Gene for replying. Yes, we used to get the info from people in the trade. It was before your time.

For me, the big shock came when someone showed a Swala Mehenge Spinel for $49,000 of questionable color, from the photo,, and then I read that report. I realize I was hospitalized for 3 months last yr with no access to a computer, so I may have missed this discussion. However, I haven't read anyone telling those that have purchased a spinel, to be on the lookout for heat. I would buy heat treated gemstones, but these spinels are now costing thousands of dollars. I'll be over this by tomorrow. I have just 2 spinels, not top color or quality.

LD. Yes I knew you were referring to Gems TV. I was making a comparison to Gem Television shows --JTV in the states.

I will tell you what I read elsewhere.-- There were many orange spessertites highly priced that didn't seem to be selling.
JTV said--no white sapphires available.

OK Gene--rubies very fine down to commerial, but not glass filled or diffused--prices?
pink sapphires same.
I know you bought tsavorite rough. What do cut stones go for at the how.
What was abundant, what was scarce.? Please answer any you wish, or none if you wish.

Annette

 

[Dioptase]

Yeah it's not new, it has been going on on a small scale since 2/3 years. Most of the spinels don't react well to heat treatment but some do.
Thankfully, labs are able to detect the treqtment without any major problem.
The new scary thing in the trade is the irradiation of emeralds now.

As for foreign substance filling; one should be wary with EVERY stone. Absolutely everything with surface-reaching cracks can be treated that way with oil, various resins and so on. Spinel is no exception.

NB: A lot of tourmalines are filled with opticon or similar polymers, be careful.

Non detectable irradiation is an issue as well, especially with tourmaline.

Actually, AGL issued a lab alert about irradiation of emeralds and they are able to tell if the stone has been irradiated or not.
We talked with Christopher Smith about irradiated rubellite during the latest HK show; apparently you can suspect if the red tourmaline has been treated or not. The treated stones have some kind of "unnatural" colour. Of course it's more it's more or less guesswork and not 100% foolproof but better than nothing.

 

[T L]

Yeah it's not new, it has been going on on a small scale since 2/3 years. Most of the spinels don't react well to heat treatment but some do.
Thankfully, labs are able to detect the treqtment without any major problem.
The new scary thing in the trade is the irradiation of emeralds now.

As for foreign substance filling; one should be wary with EVERY stone. Absolutely everything with surface-reaching cracks can be treated that way with oil, various resins and so on. Spinel is no exception.

NB: A lot of tourmalines are filled with opticon or similar polymers, be careful.

Non detectable irradiation is an issue as well, especially with tourmaline.

Actually, AGL issued a lab alert about irradiation of emeralds and they are able to tell if the stone has been irradiated or not.
We talked with Christopher Smith about irradiated rubellite during the latest HK show; apparently you can suspect if the red tourmaline has been treated or not. The treated stones have some kind of "unnatural" colour. Of course it's more it's more or less guesswork and not 100% foolproof but better than nothing.

I spoke with him via email and he told me that there is no way to tell if red tourmaline has been untreated or not. I have heard that if they have a brown modifier, they're probably not treated, but the stones with brown are not the expensive ones.

 

[Dioptase]

No accurate, scientific method for sure. That's why it won't appear on any report. You can still suspect some stones and stay away from them. Again it's more guesswork than anything else.

 

[PrecisionGem]

Hi,

Thanks Gene for replying. Yes, we used to get the info from people in the trade. It was before your time.

For me, the big shock came when someone showed a Swala Mehenge Spinel for $49,000 of questionable color, from the photo,, and then I read that report. I realize I was hospitalized for 3 months last yr with no access to a computer, so I may have missed this discussion. However, I haven't read anyone telling those that have purchased a spinel, to be on the lookout for heat. I would buy heat treated gemstones, but these spinels are now costing thousands of dollars. I'll be over this by tomorrow. I have just 2 spinels, not top color or quality.

LD. Yes I knew you were referring to Gems TV. I was making a comparison to Gem Television shows --JTV in the states.

I will tell you what I read elsewhere.-- There were many orange spessertites highly priced that didn't seem to be selling.
JTV said--no white sapphires available.

OK Gene--rubies very fine down to commerial, but not glass filled or diffused--prices?
pink sapphires same.
I know you bought tsavorite rough. What do cut stones go for at the how.
What was abundant, what was scarce.? Please answer any you wish, or none if you wish.

Annette

"Before my time..." Thanks for the compliment, but actually I'm pretty old, or at least feel it!

I was only in Tucson for a few days this year, as I have my trips pretty down pat, and can see everyone I need to in just a few days. I focus mainly on rough stones, although I did do some shopping for cut blue sapphire to recut. Walking around I could see a lot of nice sized rubies, maybe 2 to 5 ct stones going for really cheap prices. I didn't stop to inquire, but I assume glass filled heavily treated material from Africa. At least at the shows I go to, there was Ethiopian opal everywhere, the prices were higher than when the material first came out a few years ago, but still pretty inexpensive.

As far as rough, everything was scarce. Most dealers had basically what was left from previous years with very little new material. The Afghans were crazy with tourmaline prices for green/blue material, even very included material. Stuff that to me was too included for me to cut was being sold for double what I would have paid for clean material.

I didn't go to the AGTA or GJX shows this year as they started 2 days after I left. Those are the bigger shows for cut stones, but there is really very little rough there, so for me it doesn't make sense to stick around eating more taco's just to window shop.

Overall, I would think one could expect to pay more for most everything this year over last, unless they are buying old goods. So it's kind of hard to gage since many dealers have years worth of cut material to sell. I do see a few guys at the shows I attend that have very well cut stones, and these do get a premium over the average commercial cut. When you walk around looking at thousands of stones, the well cut stones do jump out at you, and that's why they can get the higher prices. As always, their booths had customers in them, if they were buying or not, I don't know. Poorly cut, typical eBay type stones are everywhere, and I don't really pay too much attention to them as I'm moving quick on a mission.

 

[Dioptase]

What Gene said. Rough is so expensive (when you find it) that it's often more interesting to buy faceted stones and recut them.

 

[smitcompton]

Hi,

Thank you so much for your answers. I like to know whats going on. I wonder if Harriet went this year? Harriet if you are out there could you add any info?

Annette

 

[PrecisionGem]

To get the kind of answers you are looking for, you would need a team of people for 2 weeks, with note books, pencils, proper training and experience to work the shows 8 hours a day. The shows are not just in one place, they basically cover the entire city. The quality of the goods varies from rubies for $10 to rubies for $800,000

What you can get is a general taste of what's going on. What is going on is there is very little quality material being mined, and what is being mined is being purchased at high prices.

 

[Harriet]

Hi Annette,

As far as I know, the irradiation of emeralds (as Dioptase mentioned) was the main worry. I'll see if I can get more information on spinel treatment.

 

[movie zombie]

and the world of color gets more interesting and more difficult to navigate.
its the disclosure part of treatment that is for me an issue. tell me the treatments and let me make my own decisions.

 

[mastercutgems]

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

This is a good but old 2005 article from GIA

I hope I am not breaking any laws on putting this on;

But it is a good article and in all reality I do not see it being a wide-spread thing as the results from heating are iffy at best; and is detectable in included pieces; and if you are paying big bucks for any gem mineral as we all suggest; get a full lab report.

I have been dealing with spinels for about 18 years and learned of heating back in late 1990's; but it was a gimmick then and did not improve the gems; we were always more leery of synthetic ones.

I guess that is why many of us cutters have and did buy big poorly cut; lightly included gems and re-cut them as you can easily test the gem on the RI meter, the digital spectroscope for key elements, and the 100x microscope. With those 3 tools you can get beyond an uneducated guess.

I guess the reason no one in the trade speaks of it often is that it is not wide-spread as we know it and that heating on a general basis does not vastly improve the quality of the original gemstone. So why do it??? Not like sapphire; but who is to say they will not spend the big bucks like in heating sapphire to really enhance the gem???

Also in Kurt Nassau's book Gemstone Enhancements there is very little written on spinels; but did say that in some Burma brown red the brown was driven away leaving a pure red; which we all know is the most sought after color; but then again it is not wide-spread at this time and the other colors like lavender, pinks, blues, etc. turned a off color not known for spinel like green and yellow or reverted back to original color; but looking at 900 to 1200 C temps which will pop an inclusion ruining the entire gem as we all know... So those are the facts as I know them at this time.

Of course all in the field correct me if I am wrong as I have been once back in 1988 LOL just joking ...I try not to make a habit of it; but it still happens

Nothing meant to hurt or insult.

Most respectfully;

Dana

 

[chrono]

Seems like the news with regards to gemstone pricing and availability is no different from last year. However, treatment continues to evolve and improve while methods of their detection continues to lag behind. It is good to know about the latest treatments as many aren't often mentioned by vendors.

 

[LD]

Also in Kurt Nassau's book Gemstone Enhancements there is very little written on spinels; but did say that in some Burma brown red the brown was driven away leaving a pure red; which we all know is the most sought after color;

Dana

............ and you can bet this is the reason that they're still trying to do it! I'm constantly amazed at how many people are looking for a "stoplight red" gemstone. Nature just doesn't produce enough!

 

[colorluvr]

Jaimeen (Prima Gems) told me that they are working on heating the pink "sleepy" spinels from Tanzania because heating does sometimes help eliminate the silky inclusions (please correct me if I'm using the wrong terminology because I don't remember his exact words, but I do know he showed me what I call a "sleepy" spinel and said it was the kind that was helped by this new kind of heating).

He also said that so far it turns them a less than premier color, but he's afraid they are going to keep at it until they get them clean AND a better color. I'm glad I bought my spinels when I did.