PSA: Red Spinel Heating Treatment Continues

[chrono]

Was checking online to my usual spinel gemmology group and noticed a lot of heat treatment going on with pink/red spinels, particularly Burmese spinels, even when the original colour was a beautiful pink. The reason for this is to meet the increased demand for pinkish red to red spinel. I'm still waiting to see more accurate before and after pictures but felt that this is important enough to warrant a heads up warning. Per Richard Hughes, many of these Burmese heated stones are also thrown into red oil afterwards to improve both the colour and clarity.

 

[SparkliesLuver]

Thank you for the notice, Chrono. That's disappointing to hear, but so it goes, I guess. A red spinel is in my future at some point, so I'll definitely have to be thorough when that time comes.

 

[MJO]

What colors and tones are heated and what are the results? Are dark tones heated like sapphire to create lighter tones or are different colors heated to produce others like purple paraiba heated to neon blue?

 

[chrono]

MJO,
So far only the medium toned purplish pinks are heated in an effort to remove the purple modifier. Debate is ongoing as to the results. Pictures show a change from bright pink to medium dark red but many noticed that the white balance is off, therefore the change is likely to be less dramatic than initially thought.

 

[VapidLapid]

Thanks for the info Chrono. Does this treatment leave any trace, or alterations in the structure that would enable labs to determine if a stone has, or has not been heated?

 

[Acinom]

Thank you for the info Chrono!

 

[chrono]

VL,
These "trials" are not done by labs or in labs; they are done in the field by miners with the intent to sell so I don't think the results have been studied officially yet. Perhaps either Vincent or Richard will pick up a sample to send to a lab? I do not know where this is headed and I am sorry I don't have any further information to share other than a heads up that nobody can presume there are no unheated spinels in the market just because the treatment seemed unsuccessful in the past.

 

[minousbijoux]

I don't know if this is an accessible link, but one such group Chrono may be referring to in case others are interested is the "Spinelover" group on Facebook: https://www.facebook.com/groups/264951586033/

 

[T L]

Thanks for the information Chrono. Very discouraging news.

 

[SapphireStyle]

Thanks Chrono. I am very disappointed by this as I have been on the hunt for a decent red spinel.

 

[minousbijoux]

Personally, fwiw, I did not find the after heat treatment to be an improvement so they clearly have a ways to go...

 

[mastercutgems]

http://static1.squarespace.com/static/509c23aee4b011ec832b1737/t/5106eb7ce4b0195ed62de82c/1359407996288/Spinel+Treatments.pdf


above is another good old read for the beginner; thank you Chrono for the update. I have been following along and find it too is low level in the hands of the miner/mine run buyer to "cash in" on the better color bringing a higher marketplace price. You see these things like the red oil, etc. when they are trying to make a quick color change as many rely on the buyer not having test instruments to see such things in the field But many have seen such a price increase in gems like the Mahenge spinels it makes those wheels of greed start turning in those heads... another sad thing...

Please stay diligent as this may be the only way we will know in time to head off a disaster as we all know many times the laboratories are 1 to 2 years behind the event and that can be costly to the consumer

Most Respectfully;

ASG Certified
Supreme Master Gem Cutter
#96CGE42

 

[chrono]

Minou,
Thanks for the SpinelLover link; yes, I was disheartened to read it there. It may not be an improvement now (who's to say when they will succeed?) but how is the average buyer to know that the spinel he/she is looking at is heated or oiled or whatever else when the general word out there is that spinel is untreated? Also, as Dana said, labs are always several years behind in uncovering treatment so it is almost a guarantee that some will be burnt by this before light is shed on this practice.

 

[T L]

Personally, fwiw, I did not find the after heat treatment to be an improvement so they clearly have a ways to go...

I liked the before pictures better as well.

 

[chrono]

Personally, fwiw, I did not find the after heat treatment to be an improvement so they clearly have a ways to go...

I liked the before pictures better as well.

Me too; the colour was a beautiful bright pink.

 

[minousbijoux]

Minou,
Thanks for the SpinelLover link; yes, I was disheartened to read it there. It may not be an improvement now (who's to say when they will succeed?) but how is the average buyer to know that the spinel he/she is looking at is heated or oiled or whatever else when the general word out there is that spinel is untreated? Also, as Dana said, labs are always several years behind in uncovering treatment so it is almost a guarantee that some will be burnt by this before light is shed on this practice.

You are absolutely right! And you are thoughtful enough to bring the information back here for others to know about as well. It is unnerving to think that something as rudimentary as a charcoal fire can make a difference to coloration. Unnerving because undoubtedly others with greater resources are on to much more sophisticated techniques and are, as is typical, ahead of the labs.

 

[minousbijoux]

Okay, the more I think about it, the more I wonder why can't the labs be keeping abreast? I mean, wouldn't we all be willing to pay $15 or $20 more for a lab report if those resources could then be used for research and development purposes to keep up with treatments? That is, to have their own staff do their own due diligence and experimentation?

 

[Marlow]

http://static1.squarespace.com/static/509c23aee4b011ec832b1737/t/5106eb7ce4b0195ed62de82c/1359407996288/Spinel+Treatments.pdf

Very interesting....

 

[chrono]

http://static1.squarespace.com/static/509c23aee4b011ec832b1737/t/5106eb7ce4b0195ed62de82c/1359407996288/Spinel+Treatments.pdf

I'd like to thank Dana for the very recently released article on spinel treatment. Just as an FYI to those who are unable to checkout the link Minou provided, the heat treatment is carried out at 700 degrees C so it makes the detection of this "low" heat treatment even more challenging for the labs.

 

[chrono]

Okay, the more I think about it, the more I wonder why can't the labs be keeping abreast? I mean, wouldn't we all be willing to pay $15 or $20 more for a lab report if those resources could then be used for research and development purposes to keep up with treatments? That is, to have their own staff do their own due diligence and experimentation?

Most labs are "for profit only" so it may not be worth their time and money to have a R&D department to sniff out the latest treatments on all the gem types out there. From my personal observation, such treatments are only discovered when a trade member notices an influx of gorgeous gems at low prices, buys some and sends of one or two to the lab for verification.

 

[dk168]

Oooer, thanks for the heads up!

DK

 

[sparkleismyfavcolor]

Egads. Thanks so much for the info Chrono!

many have seen such a price increase in gems like the Mahenge spinels it makes those wheels of greed start turning in those heads... another sad thing...

So true, and such a shame.

 

[VapidLapid]

Ah, this brings back memories of gently warmed good times, eating traditionally heated holiday cookies and roasting spinels on an open fire.

 

[LoversKites]

http://static1.squarespace.com/static/509c23aee4b011ec832b1737/t/5106eb7ce4b0195ed62de82c/1359407996288/Spinel+Treatments.pdf

Thanks for the article. I remember reading it a few months ago but it's good to refresh my memory and to be aware of the new heating done to red spinel.

 

[Dioptase]

I'm not truly surprised some people would try to heat Burmese spinels; some Tanzanian spinels are heated as well now, to drive out the silkiness.
While uncommon, I've seen a few very fine and large (over 5 ct) red spinels heated. As far as the Tanzanian stones go, the labs were able to tell if the stone was heated or not so far.