Heated vs Unheated Sapphire

[Double E]

Dear all,

There's a few questions that I keep thinking about and wish to understand how this community thinks.

Definitely I am not being torn between a heated stone & a unheated one as I am not buying right at this moment, and here I am excluding all other treatments, so heated = heat only, for unheated I mean totally untreated.

Apologies if my questions sounds illogical, lacking scientific knowledge or whatsoever, but that's exactly why I would like to ask. So here we go:

1) How rare and accessible are those untreated sapphires compared to heated ones in the market?
I've read the pinned thread on this sub forum & believe most likely this also depends on the varieties of sapphire, but just want to have a general idea, and appreciated if insights from professionals are available. At least I have read or look at some materials that it's only 1/1000 of the gem grade stones are nice enough to leave them unheated.
However, there seems to be a contradictory impression that unheated stones are kind of readily available many places / shops / sellers on the internet. Yes it's what it looks like online, so is it just an impression, and probably a misleading one while sellers do exist with plentiful supply of unheated stones?
2) What are different on a sapphire after it's heated, beside colour and clarity improvement?
Anything being altered in terms of integrity, surface of the stone (which may not be visible for naked eye but actually exists), etc.
3) How correct is it to say that a rough of sapphire has also undergone similar "heating" when they were formed under ground ("heated by nature")? If so, what's the technical / physical differences between "heated by nature" & "heated by men"?
I even suspect there could be cases when stones are certified as heated by even top labs, when it's actually not and at most heated naturally in deed.

 

[caolsen]

Assuming by ‘heat‘ you mean, traditional heating of the rough. Assuming that’s the case, it’s my understanding that beyond color and dissipation of silk nothing else about the stone changed and therefore durability remains excellent, based on clarity.

To me is question of heat or no heat is simple - are you willing to pay for the color you want if the stone is not heated? The VAST majority of the sapphires in the world are or were heated. The ‘unheated is better, more rare thing’ is a new phenomenon. That stunning sapphire suite the Queen of The Netherlands has or Di’s engagement ring - heated.

And we all know stones are not investments so thinking you’ll make money by buying unheated as an investment feels like a non-starter to me.

I own both, full disclosure. But a sapphire of the deep, royal blue I love or cornflower blue others love without heating in a decent size with good clarity can be astronomically expensive. If you want a suite of sapphires or a band or halo, you’ll need heated stones to achieve consistency.

If you want a lighter blue or teal that the earth produces, go for it - buy unheated. I did

Heated:

No Heat:

 

[Double E]

Assuming by ‘heat‘ you mean, traditional heating of the rough. Assuming that’s the case, it’s my understanding that beyond color and dissipation of silk nothing else about the stone changes and therefore durability remains excellent.

To me is question of heat or no heat is simple - are you willing to pay for the color you want if the stone is not heated? The VAST majority of the sapphires in the world are or were heated. The ‘unheated is better, more rare thing’ is a new phenomenon. That stunning sapphire suite the Queen of The Netherlands has or Di’s engagement ring - heated.

And we all know stones are not investments so thinking you’ll make money by buying unheated as an investment feels like a non-starter to me.

I own both, full disclosure. But a sapphire of the deep, royal blue I love or cornflower blue others love without heating in a decent size with good clarity can be astronomically expensive. If you want a suite of sapphires or a band or halo, you’ll need heated stones to achieve consistency.

If you want a lighter blue or teal that the earth produces, go for it - buy unheated. I did

Heated:

No Heat:

Thanks for sharing those lovely pictures.

And yes, I do mean the standard or low heat only, which is either the standard electrical furnace or a conventional blowpipe way of heating.

If I was to consider buying, I admit that I may still be slightly influenced by that "Unheated is better, rarer" thinking. Not strong though. The tolerance on the price difference depends on how big is the stones being considered. Let's take a 2ct. vivid blue or pink as example, how much should one expect to be that gap in $?

And appreciate for your reminder on the "investment" thinking, luckily I care more about the beauty of the gem than it's potential return of money My question would rather be, should we expect a general hue, saturation or tone difference on top colour heated vs unheated (as dramatic as yellow sapphire)? For example if there’s a so strong saturation that heated can’t reach or the other way round? But this is actually hard question to answer, as every ingle stone could actually vary in hue, saturation, tone... would love to hear how everyone thinks.

 

[caolsen]

My understanding, and do check this, is that graded or certified vivd pinks sapphires without any heating are exceptionally rare with good clarity. So you’re looking at 10x the costs between heated and non-heated with good to excellent clarity.

 

[PrecisionGem]

Let's look at a 2 ct. Extra fine quality pink.

Wholesale prices:

Heated $3750 per ct.
Unheated $6000 per ct.

 

[PrecisionGem]

Another pricing source lists this pink sapphire heated as $2400 per ct and $4000 unheated.

 

[Double E]

Let's look at a 2 ct. Extra fine quality pink.

Wholesale prices:

Heated $3750 per ct.
Unheated $6000 per ct.

Thanks. That allow some clues definitely. It’s really an obvious price gap that not everyone is willing or comfortable to deal with. And believe it’s even harder, if possible, to get a good cut for unheated, no one want to cut away that rare material…

 

[icy_jade]

Not an expert by any means but just some thoughts…

1) How rare and accessible are those untreated sapphires compared to heated ones in the market?

Typical jewelry stores sell commercial grade heated gems. I would say that unheated is available from specialist jewelers and is still accessible, but it’s more for a niche market so you need to know where to go? So it’s not unaccessible but it’s not all that common the way you think it is. I think maybe it’s a bit of a skewed perspective online/here since you are in a jewelry forum with some folks who prefer untreated gems

3) How correct is it to say that a rough of sapphire has also undergone similar "heating" when they were formed under ground ("heated by nature")? If so, what's the technical / physical differences between "heated by nature" & "heated by men"?

I don’t agree with that. Maybe for low heat (and low heat is like 1000C) but certainly not for most of the heat treatment in the market. Else the labs wouldn’t be able to detect heat treatment right?

Here are some articles that I think is useful to get a better understanding of the types of heat treatment and the effect on heated sapphires:

Madagascar Sapphire: Low-Temperature Heat Treatment Experiments

Madagascar is one of the world's top sources for fine blue sapphire. Lotus Gemology conducted heat treatment experiments to better understand this material and how it responds to heat treatment.

www.lotusgemology.com

Pressure Heated Sapphire • Squeezing Sapphire • Corundums treated with high temperatures and low pressure (HT+P)

Sapphires heated with high temperatures and low pressures (~1kbar) first entered the market in 2009, becoming more common since 2016. This article examines the process in detail and looks at the question of whether a separate disclosure is needed for the treatment.

www.lotusgemology.com

Personally, I much prefer unheated as there is something magical to me about a gem that looks just like that with some polishing/cutting and without any invasive human intervention. I have different tolerance for different gems - like I don’t buy treated diamonds either but am sort of ok with some gems where you can’t really tell if they are treated even if you send to a lab.

To use a PS phrase, it’s a “mind clean” type of thing. Many (most?) people are fine with heated sapphires so I don’t think there is any right or wrong here, just personal preference.

All unheated:

 

[PrecisionGem]

I have had a Lake Baringo ruby come back from the AGL as heated, when I know for a fact the stone was not heated. These little stones were shot out of a volcano long ago, and heated by the earth on the way out. They are picked up on the ground by the local people. Yet the lab thought they saw indications of heat treatment, and flagged the stones as heated.

 

[icy_jade]

I have had a Lake Baringo ruby come back from the AGL as heated, when I know for a fact the stone was not heated. These little stones were shot out of a volcano long ago, and heated by the earth on the way out. They are picked up on the ground by the local people. Yet the lab thought they saw indications of heat treatment, and flagged the stones as heated.

That’s interesting and I wonder where else sapphires or rubies may be wrongly identified as heated when they are naturally heated. Can certainly see that happening if the gems are in a volcanic region.

 

[LilAlex]

If you want a lighter blue or teal that the earth produces, go for it - buy unheated. I did

I don't think the palette is constrained by heated vs. unheated; there are unheated deeps, royals, cornflowers, pastels, and of all degrees of vividness.

 

[Double E]

I have had a Lake Baringo ruby come back from the AGL as heated, when I know for a fact the stone was not heated. These little stones were shot out of a volcano long ago, and heated by the earth on the way out. They are picked up on the ground by the local people. Yet the lab thought they saw indications of heat treatment, and flagged the stones as heated.

This is exactly what I think there’s a chance to happen irl.

 

[LilAlex]

This is exactly what I think there’s a chance to happen irl.

"Basaltic sapphires" are actually enveloped by lava -- yet they come in heated and unheated flavors. The issue is when it hits the heat.

This reminds me a little of the vendors who swear that their fissure-filled rubies just got a little bit of stuff on them in the crucible by accident by bumping up against those smelly no-good stones -- as if no one ever thought of having two crucibles so they could charge 100X more for rubies uncontaminated by flux.

This is the "It was only driven by a little old lady to church on Sunday" routine for rubies.

 

[icy_jade]

I don't think the palette is constrained by heated vs. unheated; there are unheated deeps, royals, cornflowers, pastels, and of all degrees of vividness.

Yeah. I’ve seen all sorts of vivid colors in unheated sapphires. May need to give up a body part to afford them but they exist.

 

[icy_jade]

This is exactly what I think there’s a chance to happen irl.

But I still would want an unheated sapphire from a reliable lab. I mean, if there are other unheated sapphires that look unheated and test as unheated, why would I take the word of the seller that it’s the lab that got it wrong and take the chance? Just go for one with no doubts right? Unless I picked up the rough from the ground myself. Otherwise a gem goes through so many hands before reaching me. Anything can happen in between.

End of the day it’s whether you are ok with a heated sapphire. Are you?

 

[Double E]

But I still would want an unheated sapphire from a reliable lab. I mean, if there are other unheated sapphires that look unheated and test as unheated, why would I take the word of the seller that it’s the lab that got it wrong and take the chance? Just go for one with no doubts right? Unless I picked up the rough from the ground myself. Otherwise a gem goes through so many hands before reaching me. Anything can happen in between.

End of the day it’s whether you are ok with a heated sapphire. Are you?

I gonna think about giving up which part of my body first

 

[icy_jade]

I gonna think about giving up which part of my body first

It’s possible to buy without giving up a body part. Some sellers have pretty scary mark-ups. Just avoid those and you should be fine.

 

[Double E]

Yeah. I’ve seen all sorts of vivid colors in unheated sapphires. May need to give up a body part to afford them but they exist.

It really depends on ones spending power and size of the stone. Personally I think the best bet is trying to look for somewhere between 1 and 2 carat which the price per carat is not as high as the above mentioned. I recalled that I’ve recently located a vivid blue heart cut slightly larger than a carat somewhere I forgot l, costs not more than 2k.

Sounds not bad right?^^

 

[LilAlex]

Personally I think the best bet is trying to look for somewhere between 1 and 2 carat which the price per carat is not as high as the above mentioned.

For an unheated blue, I think the best value is a lovely well-cut pastel or even a not-quite-cornflower; they can still be gorgeous. Only folks here "know" to covet a true royal blue or quintessential cornflower, etc.

 

[Sydneyphoenix]

To me is question of heat or no heat is simple - are you willing to pay for the color you want if the stone is not heated? The VAST majority of the sapphires in the world are or were heated. The ‘unheated is better, more rare thing’ is a new phenomenon. That stunning sapphire suite the Queen of The Netherlands has or Di’s engagement ring - heated.

Didn’t know Diana’s (and now Kate’s) engagement ring sapphire is heated, never read about it, do we have any sources?

Speaking of decent supplier of unheated (and heated) sapphire, you might consider harassing Wai Yan in Melbourne, Australia; the Lotus certificate for the 1.85ct Burmese unheated sapphire I paid deposit for came through as “Cornflower blue” contrary to expectations of “Velvet” or “Royal” blue, and while monikers don’t mean a lot, I will take it. I paid the rest of the cost (also bought a pretty semi-black opal) and it’s now on the way; will report when I get it in person. Mr Yan has many other samples of unheated (and heated) sapphires he showed me, both Burmese and Ceylonese-that I considered, one might be actually superior colour but a bit too dark for my taste and much more expensive.


Also a site that has a bunch of sapphires including unheated Ceylon and Burma

Buy Natural Blue Sapphires - Blue Sapphire for Sale | Starlanka.com

Find your ideal Blue Sapphire from our selection of top-quality gemstones for sale. Elevate your style with a Blue Sapphire today.

www.starlanka.com

EBay merchants like GemSupplier seem to have several as well, nowhere near as many good Burmese rubies available online…

 

[Double E]

For an unheated blue, I think the best value is a lovely well-cut pastel or even a not-quite-cornflower; they can still be gorgeous. Only folks here "know" to covet a true royal blue or quintessential cornflower, etc.

Am I right that you mean generally top color grade term like royal blue and cornflower blue are not widely desired or even known by consumers outside PS?

 

[Double E]

Didn’t know Diana’s (and now Kate’s) engagement ring sapphire is heated, never read about it, do we have any sources?

Speaking of decent supplier of unheated (and heated) sapphire, you might consider harassing Wai Yan in Melbourne, Australia; the Lotus certificate for the 1.85ct Burmese unheated sapphire I paid deposit for came through as “Cornflower blue” contrary to expectations of “Velvet” or “Royal” blue, and while monikers don’t mean a lot, I will take it. I paid the rest of the cost (also bought a pretty semi-black opal) and it’s now on the way; will report when I get it in person. Mr Yan has many other samples of unheated (and heated) sapphires he showed me, both Burmese and Ceylonese-that I considered, one might be actually superior colour but a bit too dark for my taste and much more expensive.


Also a site that has a bunch of sapphires including unheated Ceylon and Burma

Buy Natural Blue Sapphires - Blue Sapphire for Sale | Starlanka.com

Find your ideal Blue Sapphire from our selection of top-quality gemstones for sale. Elevate your style with a Blue Sapphire today.

www.starlanka.com

EBay merchants like GemSupplier seem to have several as well, nowhere near as many good Burmese rubies available online…

For the inventory in Starlanka, it surprised me that many of their unheated blue sapphires are not as expensive as I imagined. Is Anyone aware of that? Is it related to the lab they use? However like AIGS which certifies many of their stones as I can see, isn’t it a reputable lab in Asia at least?

 

[Sydneyphoenix]

For the inventory in Starlanka, it surprised me that many of their unheated blue sapphires are not as expensive as I imagined. Is Anyone aware of that? Is it related to the lab they use? However like AIGS which certifies many of their stones as I can see, isn’t it a reputable lab in Asia at least?

If I want to buy inexpensive decent sapphires I will look at the store.

 

[Sydneyphoenix]

If I want to buy inexpensive decent sapphires I will look at the store.

And yes, AIGS is quite reputable, had pretty strict criteria for jade grading as I found out an expensive way…

 

[caolsen]

Didn’t know Diana’s (and now Kate’s) engagement ring sapphire is heated, never read about it, do we have any sources?

Speaking of decent supplier of unheated (and heated) sapphire, you might consider harassing Wai Yan in Melbourne, Australia; the Lotus certificate for the 1.85ct Burmese unheated sapphire I paid deposit for came through as “Cornflower blue” contrary to expectations of “Velvet” or “Royal” blue, and while monikers don’t mean a lot, I will take it. I paid the rest of the cost (also bought a pretty semi-black opal) and it’s now on the way; will report when I get it in person. Mr Yan has many other samples of unheated (and heated) sapphires he showed me, both Burmese and Ceylonese-that I considered, one might be actually superior colour but a bit too dark for my taste and much more expensive.


Also a site that has a bunch of sapphires including unheated Ceylon and Burma

Buy Natural Blue Sapphires - Blue Sapphire for Sale | Starlanka.com

Find your ideal Blue Sapphire from our selection of top-quality gemstones for sale. Elevate your style with a Blue Sapphire today.

www.starlanka.com

EBay merchants like GemSupplier seem to have several as well, nowhere near as many good Burmese rubies available online…

On the Di Sapphire question, a source can’t be quoted, per se, but every time that ring is in the spotlight Garrad’s original catalogue piece description is brought up. It was an off the shelf purchase not a commission and the original listing doesn’t call out anything about it not being heated. As is standard, if not specified as non-heated, a sapphire of that color is assumed to be heated.

A in the late 1970’s, It was absolutely normal to heat the finest of sapphires to get ‘color’ consistency.

 

[caolsen]

For the inventory in Starlanka, it surprised me that many of their unheated blue sapphires are not as expensive as I imagined. Is Anyone aware of that? Is it related to the lab they use? However like AIGS which certifies many of their stones as I can see, isn’t it a reputable lab in Asia at least?

What is the clarity? Heating improves or changes color and clarity. Clarity is where heating, to me at least, has the most benefit. I don’t like silky stones.

 

[caolsen]

Am I right that you mean generally top color grade term like royal blue and cornflower blue are not widely desired or even known by consumers outside PS?

I think royal (deep or light) and cornflower are the most sought after colors of blue sapphires on the open market. Pretty sure the market data would show that.

Blue sapphires are not even close to being the most rare sapphire color, but they are the most sought after and hence have the highest going price per carat outside of pads.

 

[caolsen]

I don't think the palette is constrained by heated vs. unheated; there are unheated deeps, royals, cornflowers, pastels, and of all degrees of vividness.

Agree, unheated blues come in all shades. Just that the deeper blues of good clarity are less common in the unheated space.

 

[Double E]

What is the clarity? Heating improves or changes color and clarity. Clarity is where heating, to me at least, has the most benefit. I don’t like silky stones.

Quite a number of them are VS or VVS. So why is it relatively lower priced? Don’t really get it. Not all of their cut is good, and usually with window though.

 

[Double E]

I think royal (deep or light) and cornflower are the most sought after colors of blue sapphires on the open market. Pretty sure the market data would show that.

Blue sapphires are not even close to being the most rare sapphire color, but they are the most sought after and hence have the highest going price per carat outside of pads.

If talking about sapphire which is not highly rare, I honestly think yellow sapphire is a lot brighter and much more affordable, a bit outside of our current discussion.