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How Can You Tell If a Diamond is Real?

Real Diamonds vs. Fake Diamonds

Natural diamonds, shining stones formed in the depths of Earth, are rare, precious, and coveted. For centuries, the scintillating beauty of a well-cut, barely included stone has reigned as the symbol of both affluence and romance. Their popularity and price point, however, have been cause for dupe and replication – there are several stones that look physically quite similar to natural diamonds, such as lab created diamonds, moissanites, cubic zirconia, and white sapphire which have different chemical properties (and a very different price point).

Real diamonds make beautiful white gold mounted engagement rings or shining wedding bands and are often used to craft fine jewelry. And as many stones can mimic the appearance of a real diamond, it is imperative to purchase high-end jewelry only from reputable sources, like GIA certified jewelers or well-known retailers.

If you’re unsure as to whether your diamond is real or not, the best way to verify it is to bring it in to a local jeweler who can use professional equipment to confirm its authenticity. If you’re short on time, there are several at-home tests that can help indicate if your diamond is real or not.

How Can You Tell If a Diamond is Real at Home?

There are seven at-home test that can help indicate if your diamond is real:

Now let’s dig in on how to perform each of these tests in the comfort of your own home.

How Do You Tell if a Diamond is Real with Water?

This is one of the most simple tests you can conduct anywhere quickly. The only ingredients you will need are water, a glass, and the loose stone in question.


  1. Set the glass on a flat surface.
  2. Fill it ¾ with water.
  3. Drop the diamond into the glass full of water.

Results: If the gem floats, it is a fake diamond

If it sinks, there is a high chance it is a real diamond.

Rationale: A diamond has a higher density than water. Consequently, if your jewelry is a diamond, it will sink to the bottom of the glass of water.

However, do not sigh in relief just yet because the gem has passed this test. Some other materials have a higher density than water and will also sink in water.

For example, carefully cut glass or cubic zirconia can fool the eye in terms of appearance. It also has a higher density than water and could easily pass the water test.

The results from this test are therefore inconclusive. You will need to use a different test to confirm that you have the real thing and not any other stone.

How Do You Tell if a Diamond is Real with Fog?

This is another easy way to test your stone without specialized equipment. First, clean up your diamond to ensure that it isn’t covered in dirt or oils (check out our full jewelry care guide here!).


  1. Bring the diamond close to your mouth.
  2. Breathe on it to make it foggy.
  3. Observe how fast the fog clears out.

Results: If the fog clears out in a second or two, then there is a high chance it is a real diamond. If it takes more than three seconds for the fog to clear, you have a fake diamond.

Rationale: Real diamonds are excellent conductors of heat; thus, they do not remain fogged up.

However, it is essential to note that some fake diamonds, such as moissanite, disperse heat at the same rate. Hence, they could easily pass this test.

Therefore, this test cannot guarantee that you have a real diamond. You still need to visit a diamond specialist for expert tests and opinions.

How Do You Tell if a Diamond is Real by Scratching It?

This outdated test was traditionally widely used to spot fake diamonds.

It involved scratching the diamond against a mirror or glass surface and observing which of the two got a scratch. It is considered a real diamond if the diamond does not get a scratch. This test evaluates the stone’s hardness and relies on the fact that real diamond is harder than glass.

However, this test is unreliable since other stones such as moissanite, quartz, and cubic zirconia are harder than glass and will also scratch the glass or mirror.

In addition to using the gem, you are testing to scratch a mirror or glass; the scratch test can entail scratching an unverified diamond with a known real diamond.

This test relies on the idea that a real diamond can scratch a fake diamond. You can therefore spot a fake diamond by trying to scratch it using a real diamond. It is most likely a fake diamond if it gets a scratch.

However, this test is not reliable because it ignores the fact that a real diamond can scratch a real diamond. This means that you might damage a real diamond while conducting this test if the gem you were testing is a real diamond.

How Do You Tell if a Diamond is Real with UV Light?

This test involves viewing the diamond under UV light (or black light). The effect that UV light has on diamonds is called diamond fluorescence. While you might see some colors such as green, white, or yellow, diamonds’ most common fluorescent color is blue.

This fluorescence comes about when the elements within the diamond’s crystalline structures absorb the UV energy and re-emit it as visible light.

All diamonds do not fluoresce the same. There are different types of diamond fluorescence which have grades according to the intensity of the glow:

After conducting this test, you cannot pronounce a diamond fake because it was not fluorescent since some real diamonds are not fluorescent. Once again, visit a diamond expert to authenticate if the stone is genuine or a synthetic diamond.

How Do You Tell if a Diamond is Real with a Loupe?

A loupe is a small magnifying glass that a professional jeweler uses to check for inclusions within the diamond.

An inclusion is an imperfection within the diamond that results from the high pressure and heat experienced during the formation of diamonds. The nature and location of the inclusion determine the clarity of the diamond.


Place the diamond under a loupe magnifying glass and observe.

Results: The types of inclusions you are likely to see include:

Rationale: Flawless diamonds are scarce. Real diamonds are therefore often identified by their inclusions. Usually, fake diamonds will be perfect with no flaws, making them easy to spot.

How Do You Tell if a Diamond is Real with Heat?

This test requires a source of fire, fireproof gloves or a pair of pliers, the diamond you want to test, and cold water in a jar.


  1. Wear fireproof gloves or use a pair of pliers to hold the diamond.
  2. Heat the diamond for about a minute.
  3. Drop the diamond into cold water.

Results: A natural diamond will remain intact, while a fake diamond will shatter.

Rationale: Real diamonds quickly disperse heat. Hence it does not experience sudden expansion and contraction. On the other hand, a fake diamond expands while being heated by the source of fire and then suddenly contracts when put in cold water, causing it to break.

Therefore, this testing method is relatively reliable in determining whether your diamond is real or fake.

How Do You Test if a Diamond is Real with a Flashlight?

When bathed in the light of a flashlight, any real diamond will shine brilliantly and if it’s cut well enough, it’ll reflect rainbows and shining white light across the room. If you shine a flashlight onto a stone and it doesn’t shine, you likely have a diamond replication. As always, it’s best to bring the stone in to a reputable jeweler to do an official test with specialized equipment.

What’s the Difference Between Diamonds and Moissanite?

Moissanite is a rare naturally occurring mineral that have the same covalent bonding structure as diamonds. These similar properties make it difficult to tell it apart from real diamonds. Using the jeweler’s loupe, an expert can identify the naturally occurring inclusions that distinguish the real diamond from moissanite. Moissanites are also presently other-worldly rainbow refraction – if there’s too much rainbow shining from your stone, it may very well be a moissanite.

What’s the Difference Between Diamonds and Lab Diamonds?

Simply put, ‘real’ diamonds come from the Earth and lab diamonds are created in a lab. As they both come from carbon particles, natural and lab diamonds often look identical so it’s extra important to have a jeweler test a stone you suspect to be a lab diamond. Often times diamonds are inscribed with their certificate numbers that you can match to GIA documents online.

What’s the Difference Between Diamonds and Cubic Zirconia?

It is a diamond stimulant, meaning that it mimics the appearance of diamonds but has significant differences. For example, cubic zirconia does not contain any carbon elements like diamonds. It also has notable differences in hardness and refractive index compared to diamonds.

You will observe a sparkling white reflection and a slight rainbow reflection for real well-shaped diamonds. On the other hand, cubic zirconia reflects a little orange light which is nowhere close to the diamond’s sparkling white reflection.

What’s the Difference Between Diamonds and White Sapphires?

White Sapphires are colorless but their glow is not close to that of natural diamonds. There is generally more of a blur to white sapphires than the clean-cut lines of a real diamond. There will also be a lot less sparkle.

In Conclusion

If there’s anything you’ve learned from this article, we hope that you’ve understood the importance of verifying a diamonds authenticity with a reputable source. While at home tests are fun and often times informative, the best route to figuring out if your stone is a natural diamond is by heading down to your local jeweler to get their expert opinion!

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