What is the difference between a heated and unheated sapphire

difference between heated and unheated sapphire


Sapphires, the third hardest mineral on the Mohs scale of hardness, are among the most famous jewels used in jewellery. However, when it comes to unheated and heated Sapphires, you'll notice that there's a significant variation between the two groups. The price of treated and untreated sapphires also differs significantly.

Natural sapphires, also known as untreated sapphires or unheated sapphires, are extremely popular and considered more of an "investment kind" due to the lack of modifications. Heating has been utilised for millennia as a therapy! If we go back far enough in history, we can see that early man was one of the first practitioners of the technique of heat treatment. Since then, it's been utilised to treat gemstones in a more sophisticated way.

What is a heated sapphire?

Heat treatment is a typical method of enhancing the colour and clarity of Sapphire. Sapphire is "cooked" in furnaces at temperatures ranging from 500 to 1800 degrees Celsius, close to its melting point. Some of the somewhat heated treated Sapphires are not inexpensive. The cost of a good one is still around $ 3000 per carat.

What is an unheated sapphire?

Although the gemstone market is inundated with heat-treated Sapphires, finding Unheated Sapphire is not difficult. Unheated sapphires are uncommon and costly, although they do exist. Madagascar, Australia, Sri Lanka, and Thailand are our suppliers for natural, unheated sapphires. Yellow, white, pink, violet, and violet-blue are some of the hues available in natural unheated sapphires. Natural inclusions in the Unheated Sapphire include fingerprint inclusions, fine, intact rutile needles intersecting at 60 degrees in the same plane or other fine needles intersecting at nearly right angles, intact two-phase inclusions, unaltered mineral inclusions, clear or opaque colour, colour zoning, and colour banding, and so on.

The difference between heated and unheated sapphire

Almost all Sapphires on the market have been heat treated. The lower the price, the more treatment in the sapphire, because the corundum's rarity determines its price. The price of Sapphire is affected by varying amounts of heat treatment. If you're buying gemstones, you should be able to tell the difference between heated and unheated Sapphire. This is a very essential skill for a buyer to master. If you do not want to be duped into buying something, you should examine the treatment's certification, and you should be aware of the certifications.

The difference between heated and unheated sapphire is that the heated sapphire has broken needles , halo around crystal incision. Whereas unheated sapphire has intact needles and only crystal incisions.  To improve the colour, offer a variety of sizes, increase the return on investment, and provide clients with a cost-effective option. Early in the supply chain, a person or corporation thought that its excavated, pre-heated stone lacked a suitable hue. They have the option of leaving the stone untreated or marking it for heat treatment.

They would not profit financially if they left the stone in its original form. However, if they enhance the colour with heat treatment, the stone becomes more marketable and they can make a higher profit. These stones are a fantastic, lower-cost alternative to natural, unheated sapphires for the consumer. Unless the stone is subjected to a further treatment, the colour of a heat-treated sapphire will stay stable and will not alter or fade. The majority of stores allow heat treatment on sapphires because of this

Whereas unheated sapphires offer a softer brilliance and a smoother surface. Heated sapphires have a glass-like surface that is harsh and unnatural to the touch. Sapphires that have not been heated and have not had their colour or clarity enhanced along the supply chain are unusual and hence more valuable than heated sapphires, which are plentiful in the market. Color, clarity, cut, crystal, carat weight, and geographic origin all contribute to the uniqueness of each unheated sapphire. Blue sapphires of fine or gem-quality are uncommon and highly sought for by collectors. A sapphire must have the following characteristics to be called gem-quality:

  • Blue in its most gorgeous colour, tone, and saturation (Color)
  • Inclusions that are insignificant to non-visible to the naked eye (Clarity)
  • To reflect the colour, a great level of brightness is required (Cut)
  • For the movement of light in the stone, a high degree of brilliance is required (Crystal)
  • a size that is modest to considerable (Carat Weight)
  • There are no man-made treatments to enhance or improve the colour or clarity of the stone (Enhancements)

How to know whether the sapphire is heated or unheated?

Obtain a certificate from a gem lab. Only a highly skilled gemologist can do this scientific evaluation, and a renowned laboratory like GIA, AGL, Gübelin, SSEF, or GRS can do it more persuasively since they have years of research data, high-tech equipment, and experienced gemologists assessing their findings. Appraisals do not count; they are solely used to determine the worth of a property. If you are making a large purchase, you should get a certificate from a recognised gemological laboratory, even if it's an extra expense. Multiple certifications are recommended for exceptionally high-end gemstones.

Which is a better investment?

The best investment is sapphires with a vivid/royal blue colour and fine clarity that have not been treated. They're getting increasingly scarce, yet demand for them remains strong. Many signature, vintage, and antique items by well-known designers are also set with natural, no-heat sapphires. While these pieces are valued because of their history, provenance, uniqueness, design, and era, the attraction of unheated sapphires is extremely precious and appealing.

Natural sapphires of high grade are becoming increasingly uncommon, and their market value has risen significantly over time. Demand has raised the value of fine gem-quality sapphires that have been heat-treated, although not as dramatically. A good sapphire, whether natural or heated, is an excellent investment.


The first step in making an informed and secure selection is to understand what you're buying. A fine untreated sapphire fulfils all of the requirements for a gemstone: it is really rare, strikingly beautiful, and extremely expensive in every way.