Authenticating a Sapphire: 6 Verification Techniques

Sapphire stones are one of the most popular natural precious stones used in the jewelry industry; their hardness also makes them useful in other areas. Over the years, these stones have come to mean different things, such as royalty, abundance, blessings, and gifts to different people.

The last thing you want is to mistake a lookalike for a sapphire stone or to get conned into buying something else when you want a sapphire stone.

identify sapphire
Lab-Created Sapphire
Image Credit: Wuzhou Fancy Jewelry

Methods of Checking if a Sapphire Is Real

There are multiple ways to check if a sapphire is real; thankfully, you can carry out most of these processes independently.

The important thing to note is that most of these means are inconclusive and would require you to use more than one method to get a total assurance that what you have is a sapphire.

1. Scratch Test

On the Mohs Hardness Scale, sapphire is the third hardest natural mineral with a hardness of 9 out of 10; surpassed by only diamond (10) and moissanite (9.5). The hardness of sapphire means that other materials cannot easily scratch it; only a sapphire or a harder material can scratch a sapphire. 

To check if the stone you have at hand is indeed a sapphire, you should use a material with less hardness to scratch the stone. If, after scratching the stone, you see any marks on it, then what you have isn’t a sapphire. To perform this experiment, you should use a stone like topaz or quartz, a hard stone but not as hard as sapphire.

The issue with the scratch test is that it would let you know if what you have isn’t as hard as sapphire, but you might have moissanite at hand and not know.

2. Magnification

Jewelers regularly use magnification to check the authenticity of different kinds of stones. Using a magnifying glass, you can see details in the stone that are invisible to the naked eyes. You can spot a fake sapphire with a magnifying glass if you know what to look for.

Firstly, it’s important to note that all gemstones have imperfections that are a natural result of their formation process; these imperfections are called inclusions. When you get a synthetically created stone, you will find that it has no inclusions and looks flawless. If the stone has no flaws or inclusions, it’s surely a synthetic sapphire– known as a flame fusion sapphire.

The most popular magnification tool jewelers use is a loupe; thankfully, they are inexpensive and easy to use, like this 60x Illuminated loupe.


When you have your loupe, it’s important to know the types of inclusions to look out for to differentiate if the inclusions you see are that of a sapphire stone. You can check out a comprehensive explanation of the different types of sapphire inclusions here.

3. Air Bubbles

Some sapphire lookalikes are made by artificially exposing glass to the processes that lead to the sapphire formation. The thing about glass is that it’s almost impossible to make a block of glass without allowing air to enter it. When air is trapped within the glass block, you can tell by the visible air bubbles in it.

On a poorly-done sapphire lookalike, you can easily spot the air bubbles with your naked eyes. However, if an expert carefully does the lookalike, you might need to use your loupe to check before seeing the bubbles. In any case, bubbles in a stone indicate that it is not real sapphire and is made of glass.

4. Breath Test

When you breathe on a sapphire stone, it usually causes a fog; however, this fog doesn’t last as long as it would on glass. Fog on most natural stones do not last up to 2 seconds, and sapphires are no different.

Hold the sapphire close to your mouth to perform the breath test and breathe hot air on it. Monitor and take note of how long it takes the fog to clear from the stone when you pull it away from your mouth.

5. Measure The Stone Density

Another way to check if the stone you have at hand is a sapphire or not is by checking its density. The density of real sapphire is 3.98 g/cm3, and anything less than or above that is not sapphire.
To measure the density of your stone, you need to have the following materials:

  • A water container that has measurement in milliliters
  • A scale that weighs in grams; the most reliable are electric scales.

With these materials at hand, the steps you are to take are as follows:

Step 1– Place the stone on your scale and record its weight.
Step 2– Record the quantity of water in your container at the start of the test.
Step 3– Place the stone into the water container carefully to avoid spillage. Wait 1-2 minutes for the water to completely settle and record the new quantity.
Step 4– Subtract the water quantity from the new measurement. 
Step 5– Divide the weight of the stone by the result you got above; the result you get is the density of the stone.

The formula for measuring the density is, therefore = Stone weight / (Quantity of water after – Quantity of water before). If the result is 3.98 g/cm3, the stone you have is likely a sapphire.

6. Have It Professionally Checked Out

The most reliable way to ensure that a stone is a real sapphire is to take it to the professionals to check it out. You can do this by either taking it to a reputable jeweler around you or an independent agency like the Gemological Institute of America (GIA). You should take your stone to the GIA for testing because most jewelers would eventually take the stone to them for testing anyway.

The advantage of testing your stone professionally is that they are more experienced and have better equipment to conduct these tests. Because of their advantage over the layman, they would not make the mistakes you might.

Also, nowadays, artificial sapphires are so well done that you would not be able to tell the difference. A professional check will let you know if the sapphire you have is natural or artificial. 

Finally, if the stone is indeed a sapphire, it would be graded so you can know its market value. Knowing a stone’s value would prevent you from selling an expensive stone for less than its worth or overpaying for one. All the information about your stone would be put together into a unique and comprehensive certificate.

Sapphire Lookalikes

Sapphire Look Alike
Tanzanite – A Sapphire Look Alike

Sapphires are mostly blue, and there are many other types of blue precious stones that you can mistake for sapphire stones. Examples of these blue stones are:

  •  Turquoise
  •  Tanzanite
  •  Gem Silica
  •  Aquamarine
  •  Black Opal

Not all sapphire stones are naturally blue; although it is not so common, there are fancy colored sapphire stones too. Quartz and glass are the two most common materials that can be mistaken for fancy colored sapphire. Manufacturers can make glass to take up any color that they want.


These tests are important to carry out so you can be sure you are not buying a sapphire lookalike for more money than you should. However, a professional test or certification is the best way to ensure you don’t make any mistakes.

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