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Electric Heat Treatment of Saphires

Hi All,

Does anyone know about electric heat treatment of Saphires

I heard places in Sri Lanka, doing a heat treatment called “Electric Heat” the treatment will last for 20 to 40 days

This treatment significantly enhances color

Please let me know from where i can learn this treatment ? and what type of Oven they use ?



I have heard of this, but, I haven’t seen it in any burner factories.

The story goes that they heat at a low temperature for a long time which doesn’t melt the rutiles in the sapphires, but still gives them more colour, so, they still certify as unheated.

I believe that this story was started outside of Sri Lanka to account for the seemingly meteoric rise in GIA certified unheated sapphires.

I believe the truth is, there are just as many unheated sapphires as there always were. Some sapphires can’t be heated because gas bubbles will expand and crack the stone. (although the new high pressure, high heat seems to have solved this problem)

Because of the massive change in the industry, everyone is certifying everything these days, I certify some stones that I sell as cheap as $250-$300.

Since there are so many more stones being certified, there are many more stones being certified as unheated.

Funny enough, my favourite broker in Ratnapura always tells me EVERYTHING is heat treated. (because he knows it will come back if it is said to be unheated and is heated)

ALL THIS SAID: I can be 100% wrong and people have systems like this running outside of burner factories.

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Thanks for your reply

This is a topic that keeps coming up as sapphires get more and more popular … especially Montana sapphires.

First, there is no such thing as an “Unheated” sapphire. Sapphires are created in heat and LOTS of it.

In reality and from lots of personal observation, there are only two categories of “natural” (made in the Earth) sapphires:

  1. Heated by Nature, not rising to the level of a treatment;

  2. Heated by man, rising to the level of a treatment.

It is time for the big labs to stop perpetuating this charade of “unheated” sapphires.

It is starting to come out finally. :smiley:

I strongly disagree mhutton.

The descriptor for GIA is: Treatment: No Indications of Heating

When we say ‘treatment’, it is understood that we are talking about human processes.

So, ‘No Indications of Heating’ is understood as ‘no human heat process’

In your benighted reply, you said “we”. Who is “we”? I also don’t see how you are qualified to interpret what the GIA said or means. GIA doesn’t certify anyone or anything, and, their Lab Reports are not admissible in a court of law because they are hearsay. They are hearsay because they are not signed by any real person who can testify to the allegations contained therein. The major labs are gaming us on the No Heat sapphire determinations. I have spent several thousands of dollars to test these labs’ accuracy with KNOWN stones and they failed miserably.

Now all you readers out there take a good look at my personal sapphire collection … I have been all over the world buying, selling, heating, and cutting sapphires and diamonds.

What I said above was based on my personal EXPERIENCE and personal scientific observations in MY Lab with all these sapphires. Sapphires are all heated by Nature OR Man OR Both … it is just a matter of level and effect. There are NO Unheated sapphires.

Now, you can believe whatever you want to believe. Enjoy. :))

I don’t doubt your knowledge or experience, and I know that what you are saying is technically true.

That said, I believe that you are being too pedantic for 99.99% of people.

Also, one could use a similar argument to say that ‘synthetic sapphire is no different than natural sapphire’ :wink:

As I said, now you can believe what you want to believe. At least I haven’t had any of the major labs be wrong on identifying a synthetic sapphire from a natural … yet.

With the advances in material science and nano-technology … that day may come. Of course, at that time, it would be time to quit gemology!! :))))))

On the stones in the above photos that say, “Need Heat”. Those stones actually need MORE heat than Nature gave them to Improve the Cutting Yield. One of the things that indicate heating by man (to the level of a treatment) is the accomplishment of a purpose of that additional heating. That is the tell-tale sign.

I have been to Ratnapura and Kandi and 90% of those finished stones started out as white sapphire. The Sri Lankans have the low temp long term heating down to a science to add/improve color and to improve clarity (related to improvement in cutting yield). The Sri Lankans KNOW which stones have not had additional heat by man. The question is … Will they tell you?! Be careful out there!! ;))

Do you know any more about the supposed ‘heating that doesn’t show heating’ technique?

Like I said, I’ve heard stories, but, never from anyone I would trust.

Hi Sky … as I said above, these heating issues are coming out. I have to know the truth as I have thousands of dollars at stake in my own stones. The link below should make you a believer that the undetectable heating by man is going on.

I hate to say it, but I have sapphires that I have bought on the streets of Ratnapura that were sold to me as HEATED and came back from two major labs as UNHEATED, and, I have sent in sapphires that were cut from known untreated rough that came back from two major labs as HEATED. It is nothing more at this time than a SWAG by these major labs as to heating from nature or man. [ A SWAG is a Scientific Wild Ass Guess. ] The major labs seem to be operating in a safe mode … IF they can see crystal inclusions in the sapphire, then they say {No Gemological Evidence of Heat Treatment} which people are erroneously calling “Unheated”; If the major labs can’t see obvious crystal inclusions, then they are calling the stones Heated. Their track record with me is 7 out of 10 WRONG. That is really unnerving when you are sitting on as many sapphires as I am. All the best to everyone out there. :smiley:

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Note about 90% of sapphire coming out white, that’s simply not true.

I’ve seen fresh out of the pit sapphire when they empty the water on a full moon and it’s not 90% white, it’s not even 25% white.

As for the electric heat, again, I think that it’s a weird rumour, ‘urban legend’ kind of thing. Gem dealers, gemologists and jewellers are incredible bullshit artists, I have to wonder if this story came from someone trying to sell a heated stone to someone who was looking for unheated.

I knew about the high pressure and vacuum with super high heat (1800c) more or less at the very beginning because people were buying up tons of grey star sapphire to treat it to come out blue, I have never seen any demand from Sri Lankan dealers for unheated goods that they can do this supposed undetectable heat to.

As for ‘buying one thing and having it certify another’, that is just part of the business.

As I said in my first reply, my favourite runner in Sri Lanka always says EVERYTHING is heat treated because he knows that people will be upset if a gem comes back as heated when someone purchases as unheated.

No offense, but, what you are saying is a similar story to the one I have heard over and over again, but, have never seen substantiated.

Again, I don’t doubt that you have a lot of sapphire and a lot of knowledge of sapphire, but, I have been around the block a few times too.

As I have already said, you can believe what you want and say what you want. However, I don’t think you are smarter than GEMGUIDE. When I say “white” sapphire that means Geuda sapphire as this is what the Sri Lankans call it. There are 7 categories of Geuda (see figure 4 of the attached GEMGUIDE article). Five of the Seven categories are White, Clear, Milky, Gray, or Cloudy. GEMGUIDE’s chart directly under Figure 1 in the attached article states, and I quote for those doubting, “[The] Estimated Percentage of Blue Sapphire Exported Annually [from Sri Lanka] Originating from Geuda Corundum [is 98%]”. Still don’t believe? Look at GEMGUIDE’s article pages 6, 7, and 8: The Clear/White Dum Geuda turns blue; The Ottu Geuda turns blue; and the Diesel Geuda turns gemmy blue too!

Now there it is right in your face … go ahead and stay in denial. These guys are a lot slicker than you think. This is not a new article either … it came out in November/December 2018 GEMGUIDE, Volume 37, Issue 6. I claim Fair Use of the article and have attached it in its entirety including the front cover and showing all the credits due the author(s). Enjoy the good news! :)))))

I like the way you think
When I need sapphire
I know to whom to talk
Add me on what app
With Kind Regards

Thanks for the PDFs mhutton, I also need to ready what the boys are doing back in my country lol. do you know how i could get a free copy of this book/issues


Hello Mr. ceylonbling … I may be going to Sri Lanka before the end of the year. GemGuide is a professional subscription for jewelry appraisers. It costs a little over $200 per year. So unless you have a friend that has a subscription, you won’t get it for free. Each issue comes out every two months showing diamond and colored stone wholesale pricing. There is also an online edition. The boys [in Sri Lanka] ARE pretty darn creative as the illustrated article clearly shows! :))))

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I’m not looking to get in a pissing contest, but, I have carpooled with Richard Drucker from Phoenix to Tucson twice and still work with a gemologist who was his partner for many years.

Am I smarter than him? I have no idea, he’s definitely a better gemologist than I will ever be.

Have I bought and sold 100x more gems over the past twenty years than he ever will? I absolutely have.

Do I know market prices better than he does? Yes, 100%, because the system Gem Guide uses for their pricing is VERY VERY GOOD, but, very few people actually buy any of the gems they are researching. There will be exceptions with stones I don’t deal in, he likely knows the pricing of Zultanite and Demantoid better than I do, but, not emerald/ruby/sapphire etc.

Going to the article you seem to be using as ‘proof’ that there is low heat, this article is about high heat, not low heat. In the industry, we have known about the ability to use Hight Heat & Pressure with Geuda for a very long time, as soon as the high heat came out, people were buying up all the grey material they could find to treat it/retreat it.

Until I see evidence or, at the very least, a scholarly article about this mysterious ‘low heat’ process, I simply won’t believe it.

I’m open to being proved wrong, but, I’ve been selling gems since I was fifteen years old and been doing it more or less independently for twenty years, and I know how to sniff out BS stories.

Note that with all the people with a ton of knowledge on this site, nobody has given any real support to this low heat process being a real thing.

Believe what you want, but, over twenty six years in the business tells me that this is an ‘old wives tale’. Although impossible to prove either way, I would bet $100 that it started with someone trying to sell a heated stone to someone who wanted an unheated stone.

I have stated several times above: Those that read what I post here are free to say and believe what they want.

It appears that you are only in a pissing contest with yourself, because as smart as you profess that you are … you still don’t know what to believe.

I’m just a messenger, and if you don’t like the message … TOO BAD.

I would suggest for you to call your buddy Richard and ask him your questions; plus contact Maggie Gabos [] and Danapala Vithala G. E. , who were the researchers for the GemGuide Article above, and ask them your questions as well. Then come back on here to post those questions asked and their answers given.

You might learn something.

Bathroom is closed now.