How to Tell if a Diamond is Real? Here Are 12 Tests You Can Try

It is common knowledge that women love jewelry, particularly diamonds. Even the proverb “Diamonds are a girl’s best friend’’ confirms the statement.

But, just as there are many fake friends, there are also fake diamonds, which can be quite heartbreaking if you possess one thinking it to be real.

Whether you have a diamond that you inherited from family members, you got one as a gift, or it is something you bought, it is always good to make sure if what you possess is real or fake.

But what exactly is a real diamond?

The answer might not be as obvious as it seems.

It is good to first define and distinguish what can be called “real” and “fake“.

When looking for diamonds it shouldn’t take you by surprise that no reputable jeweler would refer to them as ‘real diamonds’.

Using the term ‘real’ might mislead people to think that synthetically created diamonds are actually fake, which is not the case. Even, you won’t find the word “fake” on Wikipedia’s page about Synthetic diamond.

A diamond, per definition, is any material that is composed of carbon which has a characteristic chemical composition and crystal structure.

And this definition can be applied to diamonds that have formed naturally in the earth as well as to the ones created synthetically in a laboratory.

So, according to the U.S. Federal Trade Commission (FTC) guidelines, jewelers are advised to clearly distinguish between natural diamonds, synthetic diamonds and imitations.

Even though per definition lab created diamonds are as real as nature mined diamonds, many people wouldn’t consider them as the “real-deal”.

Lab created diamonds should not be mixed with diamond simulants.

While lab created diamonds have the exact same characteristics as real diamonds, the diamond simulants only resemble the appearance but differ in properties.

In other words, they are fake!

In the group of fake diamonds we can classify both, man-made simulants, and some natural gemstones used instead of diamonds.

Among the most common gemstones that are used as diamond imitations or diamond alternatives we can include the cubic zirconia, white sapphire, and moissanite. The list is not exhaustive, so what follows is a short overview of the properties of fake diamonds.

If you’ve stumbled upon a fake diamond there is a high chance that it will be a cubic zirconia.

It is probably the most widely-recognized fake diamond on the market today. And this has been the case ever since it appeared on the market, back in 1976.

The cubic zirconia is a synthetic stone made from the crystalline form of zirconium dioxide.

Cubic Zirconia

For the untrained eye, noticing the difference between a real diamond and a cubic zirconia stone can be quite a challenge.

The stone of the cubic zirconia is hard, but it’s not as hard as a diamond. It is optically flawless and most of the time colorless. Over time it is likely to get scratched, unlike the diamond, which keeps its quality. As far as value is concerned, it’s only a small fraction of what a diamond with the same size and appearance would cost, which kind of explains why it’s so commonly used to trick people into thinking that they’re paying for a diamond.

This stone does occur naturally, but it is so rare that nowadays all moissanite is lab-created. In terms of characteristics, its hardness and sparkle are really close to those of a diamond.

The moissanite can even give more sparkle than a diamond, but more on that in the Sparkle test bellow.

However, there are two things that can help you distinguish between a moissanite and a diamond.

The first difference is the color.

While both stones can be yellow, clear or green, the stones that have a naturally red, blue, brown, black, or purple tint are most likely diamonds.

Natural diamonds have more saturated and purer colors of the stone, whereas the stone of the moissanite seems to be changing colors as it disperses light throughout the stone.

1.5ct Moissanite, Custom Cut

Second, the weight of the gem can be used to determine which stone you may possess.

If you have two stones of the exact same size and physical shape, the one that weighs considerably less will be a moissanite.

Of, course if it’s not some other diamond imitation.

Read our article Moissanite vs. Diamond and find out more about this precious stone.

White sapphire is a precious gemstone that occurs naturally and is colorless.

In terms of quality, the gems share many characteristics, so you might struggle trying to distinguish between a sapphire and a diamond.

The gems are quite similar in terms of size, color purity, saturation, strength, and solidity.

Actually, the diamond is the only stone that is harder than a white sapphire, so weight is not something that you can use to immediately know what you’re dealing with.

If you want to differentiate between a diamond and a white sapphire, you’ll need to dig a little deeper. One thing that can show you whether you have a diamond or a white sapphire is the shape formation and minerals.

While white sapphires form as corundum-based, hexagon-shaped crystal chunks, diamonds form as carbon crystal pieces which can be square or cubed.

These differences in shape and minerals bring about different light reflection and refraction pattern.

Another thing that can be a giveaway sign is purity. While sapphires in general do form in numerous colors, the white ones are considered completely pure with no traces of other colors or even murkiness.

Diamonds, on the other hand, even when they’re flawless they are not completely pure and perfect and have some traces of other colors.

While white topaz might look a lot like a diamond, its qualities are far from those of a real diamond.

White topaz is a natural stone that is soft which means that can be easily scratched. This makes the stone quite cheaper than a diamond.

Being a natural gemstone, white topaz can often contain some internal imperfections or impurities in the same way as diamonds do.

Even though the stone is colorless, these impurities may affect its color.

Just as the white topaz, zircon is a natural stone.

It can appear in various colors, but it can also be colorless.

As far as quality is concerned, it is not as hard as cubic zirconia.

Zircon is often used as a cheap alternative to diamond in engagement rings with colored stones.

Might sound improbable, but glass can really resemble a diamond due to its clarity and sparkle, so it can easily be mistaken by a novice.

Upon closer inspection, it is obvious that glass has neither the toughness nor the brilliance of a diamond.

What’s more, the glass is more transparent than the diamond.

There are a number of tests that can be performed even at home in order to check the authenticity of a diamond.

Although no test should be regarded as conclusive, they are a good indicator and start off point in assessing your stone.

There are a couple of tests that require nothing but good observing skills:

This is probably the simplest and quickest test that you could perform to check the authenticity of a diamond.

Before attempting the test, make sure that the stone is clean and not covered with any oil.

Place the stone in front of your mouth and breathe onto the flat surface in order to make it foggy.

Pay close attention how long it takes for the fog to dissipate. If the fog clears up in one or two seconds, that’s a great sign and it means that you should be holding a diamond in your hand.

If the stone remains fogged for several seconds, the likelihood is that you’re holding a fake diamond. This happens because diamonds conduct and disperse heat very effectively, so no condensation can stick to the surface longer than a second or two.

The scratch test may not be the best test to check if the diamond is real, but it’s good to be aware of it. Since the diamond is one of the strongest substances on earth and is ranked hardest on the Mohs scale, you can very easily cut through glass with it. So, if you have a plate of glass and a loose diamond you could try the scratch test. Simply put the glass on a table, or any flat surface and use your diamond to scratch it. If the stone leaves a scratch on the glass, there are chances that it is a real diamond.

Note: When doing this test it is possible to damage or chip your diamond, so take that into consideration before attempting. Also, there may be some other gemstones that can cut through glass as diamonds. Thus, the test may be a bit risky and inconclusive.

The newspaper test is also known as transparency or refractivity test as it relies on the reflection of light to tell whether a diamond is real or not.

A diamond’s inherent quality is to refract or to sharply bend the light which is passing through. Diamonds refract the light in various directions and not linearly, something which is not the case of counterfeit products.

So the test is the following: 

First, you will need a newspaper and a loose diamond, preferably a larger stone.

The diamond should be facing down on a section of text in the newspaper.

If you can read the print or see black smudges, then I’m afraid that’s bad news – the stone is most likely fake.

Diamonds refract light in such manner that you will not be able to read the print below.

The newspaper test: Real Diamond vs Glass vs Cubic Zirconia

Note: If you don’t have a newspaper available at the moment, the dot test is a perfect alternative. Take a white piece of paper, place it on a flat surface and draw a small dot with a pen. Lay the stone over the dot, with the pointed end of the stone looking up. When you look down onto the paper, due to diamond’s powerful refractive qualities, you shouldn’t see the dot if you’re holding a real diamond. If you see the dot or even notice a reflection in the diamond, then the stone is not a real diamond.

Another really quick and simple test is the water or the floating test.

You’ll only need a glass of water, a loose diamond and 2 minutes.

Take a glass that is ¾ full with water and carefully drop the diamond inside.

The stone of the diamond has a high density, so when placed in water it will sink to the bottom.

If the stone floats on the surface or is just right underneath, you are holding a fake diamond.

Note: If the stone is set into metal, like on a ring, it will most likely sink when dropped into water, so the test is not applicable to stones that are not loose. Also, not all fake diamonds float into water, so if the stone passes the test, it’s best to perform an additional test.

For this test you will only need to use your eyes.

Place your diamond under a regular lamp and simply observe the way the light reflects off of the stone.

Diamonds are great at reflecting light and provide exceptional sparkle.

They are well-known for the brilliance, fire and scintillation. If you’re holding a real diamond, you should be able to notice bright shimmers of white light bouncing off the diamond and colorful light reflections.

The white light that is bouncing off is known as the diamond’s brilliance whereas the rainbow light that is reflected is called its fire.

You can easily distinguish between diamond and moissanite. The latter carries much more sparkle than a diamonds, although it’s because it has a different faceted pattern which creates that disco-rainbow effect.

In the case of Cubic Zirconia, a diamond is superior with its unmatched brilliance.

Diamond vs Moissanite vs Cubic Zirconia in the Sparkle Test.

The general rule: When trying to distinguish between a real and fake diamond, counterfeit stones will display a colorful sparkle internally.

There are some other tests that can be performed along with the use of some instruments:

This test is quite quick to do and you will only need an ultraviolet or black light and a diamond.

Turn off the lights and hold the stone in front of the black light. If you see a medium to strong color of blue, you can rest assured that you’re holding a real diamond.

If you see a slight green, yellow or gray fluorescence, your stone is not a real diamond.

Note:This is not a conclusive test since only about one-third of all diamonds will reveal a blue fluorescence.

In order to see if a diamond is real you can inspect it with a magnifying glass or even a jewelry loupe.

A loupe is a type of magnifying glass that has no handle attached and its lens frame is slightly more conical than that of a regular magnifying glass. It is mostly used by jewelers and watchmakers to see small details up close. It’s especially needed when jewelers inspect diamonds for class and clarity.

So if you decide to do this test and don’t have one, you can easily get it online, at a jeweler’s or craft store.

In order to do the test, you will need to closely examine the diamond for inclusions or flaws. Since diamonds occur naturally, they most likely have some tiny natural imperfections.

Then, look for small flecks of minerals or slight color changes. You may be able to notice a small piece of carbon or a white spot that looks like feather.

Cubic zirconia and other synthetic diamonds like moissanite will not have such inclusions as they are internally flawless.

Note: Diamond-specific inclusions will confirm that you’re holding a genuine diamond, but bear in mind that although rare, there might be some internally flawless diamond. Also, lab-created diamonds in almost all of the cases do not have any imperfections since they’re created in controlled environments, and as stated above, they’re as real as the ones formed naturally.

This test is as exciting and unpredictable as its name.

To perform The Fire Test, you will need a loose stone, a lighter and a liquid container such as a glass filled with cold water.

Also, you will need a set of plyers or fireproof gloves to hold the stone.

Heat the stone for around 30 seconds and then drop it immediately in the glass of water. If the stone is a real diamond, it will remain unharmed and will simply fall to the bottom. The reason for this is that diamonds are one of the strongest materials on the planet and are unresponsive to high heat. In fact, they were formed under intense heat and pressure billions of years ago, so when you heat a diamond, the heat disperses quickly and the change in temperature doesn’t affect the diamond.

However, if the stone is fake, it will shatter to pieces. The quick expansion and contraction of heat causes weak materials such as cubic zirconium or glass to crack and break.

Note: The good thing about this test is that its results are conclusive. The bad news is that if your stone is not an authentic diamond, after the test you will possess no stone whatsoever. So, if you’re not concerned that you may damage or ruin the stone, feel free to try it out.

A rather simple test if you possess a diamond scale. Since you probably don’t, it might be a good idea to take the stone to a local diamond jeweler who will be able to weigh the stone for you. A sign which shows that you’re definitely dealing with a fake diamond is if the stone weighs more that an actual diamond of the same size and shape. Fake diamonds such as cubic zirconia weigh 55% more than an actual diamond of the same properties. If you possess a grading report for the diamond you can match it to the weight recorded.

Note:Apart from the scale, you will need two stones of the same shape and size, and you will need to be sure that one of them is real. So, from simple, this fact probably makes the test a bit impractical and difficult to perform.

While most of the tests so far require your diamond to be loose, this test actually relies on the mounting. Real diamonds will be set in high quality jewelry such as white gold, platinum, yellow gold, pave or side-stone setting and halo setting rings.

Look on the inside band of the ring for markings. The notes 10K, 14K, and 18K stand for gold, PT and Plat for Platinum, and the numbers 585, 770, and 950 can also stand for gold and platinum. However, if you notice a C.Z stamp or engraving, be sure that indicate that the stone is a cubic zirconia, and not an authentic diamond.

Among the tests that require special instrument is the test for thermal conductivity.

Gemologists often have in their tools a thermal conductivity probe or meter.

With this tool they are able to determine the thermal conductivity of a gemstone. D

Diamonds are a very effective heat conductor, which means that they will disperse heat quite rapidly after being warmed. If the stone disperses heat at a slower rate, it is a sign that the stone is probably fake.

Note:The synthetic moissanite stones possess a similar or sometimes equal heat conductivity, which makes the test inconclusive with diamonds. So, if the stone passes the test, make sure you use another one that will rule out the possibility of it being a moissanite.

Apart from thermal conductivity, the diamonds can be tested for electricity conductivity.

This test can be performed by a jeweler or gemologist. Diamonds are better at conducting electricity than other stones, including the moissanite. So, an electricity tester can tell you whether the stone is real or counterfeit.

No single test will tell you for sure if a diamond is real or not, but a combination of tests might give you an answer.

Are you prepared to test your diamond? We would like to hear your results.

I love diamonds like every woman does, but I like to go beyond and research the topic to the ground.