Today’s article will be about the difference between Unheated and Heated Sapphires, how to identify whether a sapphire is heated or whether the sapphire is unheated, how each type has a different buyer in the marketplace, the different types of treatments in Sapphires today.

Heat treatment of Sapphires

Sapphires, which are the third hardest mineral on the Mohs scale of hardness, they are some of the most common gemstones, commonly worn in jewelry. If you talk about unheated and heated Sapphires, then you will come to know that there is a big difference between both the Sapphire categories. The price also varies largely between the treated and untreated sapphires. The Natural Sapphire, also known as Untreated sapphire or Unheated Sapphire, are exceedingly trendy and are more of a “Investment type” due to no treatments being present in them.

In the market, almost 95% of the Sapphires are heat treated. The higher amount of treatment in the sapphire, the lower the price, as the corundum’s rarity creates its price. There are different levels of heat treatment which affect the price of Sapphire (However most labs in 2016 only give a Heated and Unheated certificate). Rubies are more valuable, which is why Gemstone laboratories are able to certify whether the Ruby is H1, H2, H3. Or the extent of heat in the ruby.

If you are a gemstone buyer then you should know how to distinguish between unheated and heated Sapphire. This is a very important skill a buyer should learn. If you do not want to be scammed for what you are buying, then you should check the certification of the treatment and for that you should have knowledge about the certifications. Oh we also have a real sapphire color chart of blue sapphire so you can see the different colors.

The difference between Unheated and Heated Sapphire is like the difference between processed and natural food. Natural food is always healthier than processed food. The heat treated Sapphire lost their effectiveness almost to zero.

Unheated Sapphire
This is true that gemstone market is flooded with the heat treated Sapphires but, it is not impossible to find Unheated Sapphire in the market. Unheated Sapphires are rare and expensive, but available. Our sources of Natural, Unheated Sapphires are Madagascar, Australia, Sri Lanka and Thailand.
The Natural unheated Sapphires are also available in different colors like yellow, white, pink, violet and violet blue. We also deal in Blue Sapphires with large size, over 2 carats, from Madagascar and Australia. The Unheated Sapphire has natural inclusions like finger print inclusions, rutile needles that are fine, intact and intersecting at 60 degrees angle in the same plane or other fine needles at near right angles, intact two phase inclusions, unaltered mineral inclusions, clear or opaque color, color zoning and color banding, etc.

Heated Sapphire
Heat-treatment is a common practice to improve the clarity and enhance the color of Sapphire. A Sapphire is “Cooked” in furnaces to temperature between 500 and 1800 degrees Celsius, which is near to the melting point of Sapphire. Some of the treated Sapphires, which are slightly heated, are not cheap. Good ones still cost upward at $ 3000 per carat.

If you are wanting to Understand quality and color in Blue sapphires then here is a brilliant video that got us 50,000 views and counting so far.

Here is a quick 3 step guide of identifying how to check the identify whether your sapphire is heated or unheated.

Things you will need before you start the process:

Once you have understood the heated/heated signs of broken needles and halo around the crystal, you can start the process as per below:

1. Use the tweezer to pick up the stone (Sapphire) in the below position:

Gemstone held by tweezer

2. Hold the x20 loupe inside your fingers and get a firm grip on the stone’s view under this loupe. After few practice sessions you will be able to get a clean view, as slight changes of angle you will find the stone will be blur. You have to get the view in a perfect clear sharp focus.

GIA Loupe x20

3. See the stone from different angles and try to find the signs of heat treatment or if you cannot, then make sure you get confirm signs of no heat treatment.

Other Common Treatments in Sapphires
Some of the other treatments are as follows:

Surface Dyes:
This is a temporary treatment which can modify the color of the gem. When a seller wants to pass off an imposter gemstone as a Sapphire, he uses this treatment. Below is the image, which will clear most of the things.

Fracture Fills
This treatment is used to mask the large and unattractive inclusions and cracks from the stone. This treatment temporarily increases the transparency and clarity. It can also change the color of the stone. Below is the image which will clear your doubts.

Beryllium treatment is used to change and enhance the color of Sapphire. It is devastating and expensive to expose this treatment in Sapphire. You can see an assortment of Sapphire heating with Beryllium. You can see that many of them change from yellow to orange and many remain blue.

Diffusion Treatment
The most common treatment is the “Diffusion- treated sapphires“. This treatment is an artificial enhancement of color and may be impossible to detect without very sophisticated Lab procedures and instruments. To enhance the color of Sapphire, this heat treatment is provided in a reducing and oxidizing atmosphere.

This treatment changes the color of the Sapphire permanently at the molecular level. This treatment is used to provide the colors which are not naturally available. You can see an example in the image below.

Usually the gemstone labs give certificates of Natural Sapphire and Heat Treated Sapphire. You can see in the images on the internet that in one certificate it is mentioned that “No indication of Heating” in the Treatment Section and in the other certificate it is mentioned that “Indication of heating”, which means that the Sapphire is Natural, but heat treated. 


Here is the conclusion – depending on what your purpose of buying a Heated or an Unheated blue sapphire would be. Each purpose with a decision on what should be chosen.

Conclusion on Heated and Unheated sapphire

If you want to Buy Unheated Sapphires, then you must complete all the checks before buying it. Unheated Sapphire holds all of its physical, metaphysical properties and natural properties. I hope this article will help you in Buying Natural Sapphires for your loved ones.

Contact us for heated and unheated sapphires
Please write us a mail on to get more information or know pricing of natural cooked or uncooked sapphires.