Heated vs Unheated Sapphire: A Guide

Heated vs unheated sapphire – if you have ever tried to purchase a sapphire gemstone or sapphire jewellery, you would have asked, heat or no heat?

Most sapphires are heat treated. Let’s say, 99%.

Thermal or heat treatment is common in commercial sapphires, as heat brings out the vivid colours of sapphires.

Points to note before reading further

    1. Sapphires that are heat treated are still considered natural, 100% natural.
    2. Unless stated and certified to be ‘unheated’ or ‘no heat’, the sapphires you see on a ring or a pair of earrings are likely to be heat treated. Heat treatment in sapphires is legal and acceptable. As a general rule when shopping for sapphires, you should always assume sapphires are heated unless they are specifically stated (and certified) to be unheated.
    3. However, colour treatment, or beryllium treatment, is illegal or unacceptable unless disclosed. Do not confuse heat treatment with chemical treatments like beryllium or diffusion.
    4. If you know the difference in the market value of heated versus unheated sapphires, you will understand why they are always certified as unheated (if they are) AND sold as unheated sapphires (ie. the status of an unheated sapphire is never ‘unsure’ or undetermined).
    5.  Heated or unheated, the demand of sapphires with vivid colours does not abate (compared to less vivid colours in otherwise natural ‘earthy-looking’ sapphires). What consistent demand does is actually to drive up the prices of even heated sapphires to a high, sometimes asking for as much as an unheated sapphire that is lacklustre in colour.
    6. In short, TWO pervasive factors determine the price of a natural sapphire: whether the sapphire is heated or unheated, and how vivid is the colour of the sapphire (sometimes called how ‘fiery’ the colour is).


Rubies and Sapphires
A medley of sapphires and rubies. Can you guess which are unheated, by sight alone? It is hard, isn’t it?


Rose Cut Sapphire Earrings
Unheated rose cut sapphires. These are unheated sapphires that are better, imho, unheated. Perhaps this is because their pastel colours are lovely in their softness, which is not what is typically coveted in sapphire colours. From an artist’s perspective, this is a heavenly palette.
Ask not “What is the price of sapphires per carat” but “What is available for sale”

Due to the rarity of unheated sapphires (that 1% in worldwide supply), it should be no surprise that market forces of demand and supply thrive when it comes to the price of sapphires.

Good quality unheated sapphires will cost you. Unheated sapphires below 2ct or 3ct are affordable, but the price jump is exponential for sapphires above 5ct.

Depending on colour (vivid/fiery), broadly speaking, unheated sapphires below 2ct to 3ct will range between USD800 per carat to USD3,000 per carat. Above 5ct, unheated sapphires may range wildly from USD3,000 per carat to USD8,000 per carat.

Above 10ct, every 5ct jump in size will raise the price astronomically.

Carat weight aside, the origin of sapphires will significantly affect the asking price. Broadly speaking, Kashmir – Burma – Sri Lanka, this preference ladder depicts the collector frenzy when it comes to the pursuit of sapphires. Note that Kashmir sapphires of quality are always the same stones sold and resold numerous times, and current production of good material from Mogok is very limited. Kashmir sapphires are not heated, while Burma sapphires are usually not heat treated.

Sri Lankan (Ceylon) sapphires are prized much higher than Montana or Australian sapphires, mostly because the colour of Sri Lankan sapphires tend to be more vivid. Many Sri Lankan sapphires also tend to undergo only low heat treatment (this varies, especially with the market being most active today).

Sri Lanka produces a wider range of sapphire than any other classic source – in fact, it’s famous for ‘fancy’ sapphires, ie. colours other than blue, including the coveted orange-pink Padparadscha sapphire.

Hence, it is truer to say that outside obsessive collector activity, demand always exceeds supply for all quality sapphires, heated or unheated, as long as the colour falls into any of the below… well, Lotus Gemology’s Ruby & Sapphire Color Types guide is a reliable benchmark, if you are interested in further reading.

Lotus Gemology
Highly Desirable Ruby & Sapphire Colour Types 
Kashmir Blue Sapphire Unheated
17.5ct unheated Kashmir sapphire. A frenzy of activity in the 1920s have effectively mined out these Kashmir deposits.


Kashmir Blue Sapphire Unheated
Kashmir sapphires command the highest prices as they are extremely rare. Kashmir mines have long stopped production for close to one whole century now. The ones available for sale (if any) were mined a long time ago and trading is limited to whatever was mined then.


Sri Lankan Cornflower Blue Sapphire
13.2ct unheated cornflower blue sapphire. The lively blue colour of this gem earns it the Lotus “cornflower blue” distinction.


Cornflower blue sapphires
So what is 13 carats like? An idea of how big, hence how rare this gem really is, when placed beside a ring.


Burmese blue sapphire sugarloaf
4.4ct unheated Burmese blue sapphire. This ‘sugarloaf’ is my favourite cut in a quality gem. It is polished rather than faceted, showing all; yet it is unlike a regular cabochon because of its pyramidal shape.


Tri colour Sri Lankan sapphire
13.8ct unheated Sri Lankan sapphire. This tri color sapphire is one of those ‘fancy’ sapphires the industry sometimes calls an “antique sapphire”, perhaps for its unique colour banding and cut at such a high carat, unusual traits which are not often observed in sapphires cut closer to present day.


Unheated Tri Color Sapphire
Consider how a simple design, like what Napoleon presented to Émilie Pellapra (she claimed to be his illegitimate daughter), can be manifested by an exquisite tri colour sapphire, surely not lacking in place to the otherwise common diamond.


Purple Blue color change sapphire
16ct unheated colour change sapphire. Another ‘fancy’ sapphire because it displays a dramatic colour change from blue…


Color Change Sapphire
… to purple! This sapphire is not just fancy for its colour change, but at 16 carats, you do not need to ‘train’ your eyes so much to perceive its colour change properties. Size consideration is important when it comes to colour change gems, if not for value then for proper visual enjoyment.


Color Change Sapphire
At 16 carats, this big, unheated and dramatic colour change is wholly Nature’s make. Can you see both the blue and purple in the colour zoning?


Color Change Sapphire
Now can you imagine this colour change sapphire in a simple lavaliere necklace?


Should I demand and/or pay for an unheated sapphire?

There are all kinds of reasons to do so and all kinds to not. It is more useful to consider why jewelry designers choose to use unheated sapphires (if so).

One reason has to do with the perception of beauty and its impact on value. Designers and high fashion want to showcase their craft and style, and sometimes to do so, it is only worthwhile to put their creative efforts to sapphires that are 101% natural (100% natural plus the superlative 1% of worldwide supply!). That is, their colours must be exactly the way they are when they are mined from the earth and nothing more is acceptable.

Consider also that sapphires sought out for occasions such as engagement or anniversary have more emotive reasons to demand for that 1%.


The Ironic War between Nature & ‘Natural’

With the world’s preoccupation with what’s natural and what’s investment quality, it is not an exaggeration to say we are caught in a balancing web of mining out Nature and insisting on Nature!

It is ironic that if every zealous individual insists on paying for only an unheated sapphire, one certain outcome is to keep pushing up its price. All while collateral damage washes across Nature’s resources and deposits.


Our World Is A Magical Smoke Screen: Heated or Unheated?

We cannot speak for other jewellers but for ourselves.

I refrain from using the term ‘ethical’ as this has become embroiled with commercial motives and the outcome is laughable – our stand then as a mindful artist-craftsman-jeweller is to assess the reason for pursuing an unheated sapphire.

Our approach is simple, and sentimental. If it is the one piece of jewelry you are likely to want or purchase (and affordability is not an issue), an unheated sapphire may be good idea.

If you already have a few jewels or will expect to have more in future, there is no rush. Forestalling desire heightens its gratification , we hear this often…

But seriously, it is the denial of immediate gratification that will leave a better place for our children. Posterity will and has always depended on the now.

In David Lynch’s world, the past dictates the future. (Yes, I do realise this statement could lead us back to where we started.)

What can you gather, just by looking at photos of the gems below? I am tempted to state which are heated, but there’s no fun in that.


Natural Blue Sapphire Ring
SIJS 3.6ct Ceylon Bi Colour Blue Sapphire Ring


Bicolor Sapphire
The cut of this “antique sapphire” is suitable for a historical Roman setting. The sapphire with its uneven facets, sides and all, is reminiscent of gold rings dug from an archeological site.


Natural Blue Sapphire Ring
These unconventional cuts allow what was originally a primitively cut sapphire to look more like a stone than like a gem, precisely what makes the ring design work. This is a sapphire with a cut that matches its colour zoning, hence the stone is a gem with a ‘story’.


Ceylon Blue Sapphire Ring
SIJS 3.6ct Art Deco Ceylon Sapphire Ring. This sapphire shade approximates Velvet Blue, always desirable.


Antique Blue Sapphire Ring
4.33ct Mid Century Platinum Ring. This sapphire shade approximates Royal Blue. Bear in mind there’s very little light here.


[February 2018 Update: watch out for more photos of more colours of more actual sapphire rings!


Gemological Labs vs Jewelers

The grading of stones generally fall into two sources: gemological labs and jewelers.

Gem labs will provide you with the basic info about identification, country of origin, and the presence or lack of treatment. Problem is, most of the top gemological labs that document sapphires and other coloured gems  don’t actually grade stones. There exists too much potential for conflicts of interest, as you may imagine. Which explains why the smaller gem labs have sometimes come in to fulfil this gap, grading in addition to identification. Here then lies possible areas for contention, which is why some stones can have two (or three) differing certification papers.

Many jewelers are also independent gemologists. Again, realistically speaking, the same potential for conflicts of interest prevail.

Our final word is this. When purchasing fine or luxury gems, it makes sense, both financially and intuitively, to consult with a jeweler/gemologist who goes beyond the identification of the gem to provide you a market-realistic grading and price guide.

Know where your cert is coming from. But get an independent grading and price information. This I find is always possible from a straightforward jeweler, who knows intimately the forces of demand and supply.

In some countries, like Singapore, no gem lab is seriously doing the grading and price information appraisal on paper, as they understand it is too unreliable when it comes to actual paying for and selling for (ie. who is buying, who is selling). This means you will be getting your grade and price information verbally.

Above paper, what your gem can fetch in the market must be realistic.

Personal Taste

If this is the case, it makes all sense to buy a gem you love, for whatever reasons that first caught your eye, understanding its draw and drawback points. Backed with a good lab’s certification and an understanding of market forces, you’ll be happy for a long time to come.

If that is not your experience, don’t blame yourself (or others) too much. Training your eye by looking at gems and educating yourself will take time. Knowing yourself is the most important, in the bigger scheme of things. The paper (or lack of) is secondary.



We will continue to update this article with new information on our journey in “secrets of the gem trade”.

Like this article? Our outsider guide to gems may interest you too.

A list of the unheated gems available for sale at Singapore Island Jewellery Store, our other store..


7 things you didn’t know about gemstones & fine jewelry
Heated vs Unheated Sapphire
heated sapphire vs unheated
how to choose a sapphire
what is an unheated sapphire
how to buy gemstones
Heated vs Unheated Sapphire
heated sapphire vs unheated
how to choose a sapphire
what is an unheated sapphire
how to buy gemstones
7 things you didn’t know about gemstones & fine jewelry
Heated vs Unheated Sapphire
heated sapphire vs unheated
how to choose a sapphire
what is an unheated sapphire
how to buy gemstones
Heated vs Unheated Sapphire
heated sapphire vs unheated
how to choose a sapphire
what is an unheated sapphire
how to buy gemstones
heated vs unheated ruby
7 things you didn’t know about
unheated sapphire for sale
how to buy an engagement ring
tips on buying sapphires
7 things you didn’t know about gemstones & fine jewelry

3 thoughts on “Heated vs Unheated Sapphire: A Guide”

  1. I learned a lot from the article. I knew nothing to start with and now know the rudiments of raw gemstone. I find the stones in an auction in their raw state interesting and will probably purchase a cheap one just to see and feel it


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