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How to Tell If a Diamond is Real? 10 Easy Ways an Tips

on June 25, 2024

How to tell if a diamond is real? There are easy ways to tell if a diamond is real or not and although these are not infallible tests, they are good to keep in mind as diamonds are high value investments, both monetary and sentimental, and are expected to be passed on to future generations or can be capitalized on in the future if necessary.

Whether you have received jewelry in an inheritance, plan to make a well-informed purchase or have received your engagement ring and are in doubt of the center diamond, this guide will come in handy.


How easy is it to tell a fake diamond at a glance?

Actually, for a person unfamiliar with the physical properties of a diamond, distinguishing between a genuine stone and a well-made imitation is kinda hard.

Stones such as colorless sapphire, colorless topaz, cubic zirconia and Moissanite are often sold as genuine diamonds, even though they have no real value.

Since a genuine diamond with good characteristics fetches a high market value, the trade in fake diamonds is a tempting activity for many alternative market vendors. Be wary of too-good-to-be-true offers.

How to avoid it? Buy your diamonds from a serious and certified supplier.

At Albert Hern we make sure that every single material used is 100% authentic and comes from conflict-free zones.


how to tell if a diamond is real


How to tell if a diamond is real: Do it yourself at home

First of all, it is important to clarify that no home method is completely foolproof when it comes to determining if a diamond is real. Only a trained expert with sufficient tools can determine this.

Some tests that you can do yourself at home if you have the time and interest to do so are the following:


  1. Water test
  2. Fire test
  3. Fog test
  4. Ultra violet light test
  5. Hardness test
  6. Refraction test
  7. Mounting test
  8. Complete reading test
  9. Point-to-point test
  10. Contrast test

Explore each of these methods and determine a group of them to evaluate the properties of your diamond before taking it for professional evaluation.


1. Testing the diamond with water

This is one of the simplest tests.

Fill a basin or container with water and carefully drop the diamond on the surface. If the stone remains floating on the bottom, in the middle or on the surface itself, you are looking at a fake.

The diamond is an extremely dense stone so it will not naturally float in water.


If the diamond sinks, is it genuine?

Not necessarily. Not all fake diamonds float on water. This means that this is not a definitive test and decreases in effectiveness as the size of the stone increases. It must be combined with other methods to be sure.


2. Knowing if a diamond is genuine by using fire

Genuine natural diamonds are formed underground in conditions of uncommon temperature and pressure.


So, how can u tell if you have a real diamond with fire? Subject the stone to a live flame for 40 seconds or more. You can use a lighter, torch or stove. Immediately afterwards, throw the stone into a bowl of cold water being careful not to hurt yourself.

If the stone discolors, cracks, chips, or breaks completely due to the temperature change, it is not a diamond.


If the diamond does not break in fire is it genuine?

Again, not necessarily. While you can be sure that a genuine diamond will not break in this manner, some imitations may not either, compounded by any possible human error in their execution.

Be aware that this method is a good guide, but it is not foolproof.

Also remember that it compromises the fake diamond (in case you want to keep it) and that if the diamond is set you risk damaging the setting.


3. How to tell if your diamond is genuine with fogging

Breath is one of the oldest and easiest techniques to implement.

Like trying to fog a window in a cold environment, exhale some warm breath for several seconds until you can fog the stone.

A genuine diamond dissipates heat instantly across its entire surface, it is impossible to fog up for more than a second or two. All other stones remain tarnished for much longer.

This is a test you should perform on large diamonds (over 1 carat minimum) as it is very difficult for you to tell if a small diamond is really tarnished.


Is every diamond that tarnishes a fake?

Not necessarily. Any oil, dirt or impurities on the surface of the diamond can cause it to tarnish longer than it should. Ambient humidity can affect the result of this test.

Depending on the diamond surface and temperature, it may require several repetitions of the test, so the method is not foolproof in all cases. It is advisable to combine it with other tests from the list.


4. Rapid ultra-violet light test to verify genuine diamonds

When a genuine diamond is subjected to black or ultraviolet light, it is 33.33% likely to glow with a blue fluorescence, virtually impossible to achieve with a fake stone.

This is a good guide that, combined with other methods, can clarify doubts about the authenticity of the diamond.


If my diamond does not fluoresce blue under black light, is it a fake?

For fear of sounding repetitive, not necessarily. Many diamonds do not have any fluorescent reaction and it is normal.


5. Is the scratch test still reliable?

For several centuries, the scratch test based on the Mohs scale was the basic method for testing the authenticity of a gemstone.

Since diamond is the hardest known naturally occurring material in the world (10), only another diamond should be able to visibly scratch it. If you rub a needle point or a shard of glass with extreme care over the surface of the diamond, it should remain completely intact.

Consider that only Corundum (like sapphire) is lower in hardness (9) and is about 5 times more brittle than diamond. It is not likely that you can scratch your stone with anything, if it is genuine.

This is usually the biggest difference between a real diamond and a fake diamond. As long as we are not talking about cubic zirconia, which can be as hard as diamond.


Is this method still foolproof today?

Some synthetic imitations of diamond are very resistant, moreover, scratching a stone aggressively can compromise its surface structure and reduce its value.

Never use sandpaper as recommended by some diamond information channels.


6. Light and refraction testing on genuine diamonds

A diamond has unique interactions with light that cannot be reproduced by other gemstones. Clarifying that light does not refer to brilliance, many fake diamonds are very bright: Moissanite and colorless zirconia are good examples.

When contrasting a genuine diamond with light, a beautiful group of effects can be noticed, like a symphony:

  • Scintillation: composed of light and dark patterns observable within the diamond as it moves under the light.
  • Glitter: A white light inside and outside the diamond with a subtle intensity.
  • Fire: As the white light is absorbed and reflected, the rest of the light bouncing inside the diamond is dispersed in multiple, rainbow-like hues and exits the diamond leaving a peculiar multi-colored effect visible at some angles. Mainly on the upper facet.

It is the balance between the three factors that makes a diamond so attractive.

To spot a potential scam, check that none of these factors are disproportionate like cubic zirconia, for example, which has excessive rainbow patterns.


Is a diamond with little sparkle a fake?

Although diamond brilliance is unique and distinguishable from other gemstones, many factors interfere with it. For starters, a fancy cut such as an emerald does not sparkle as much as a round cut. The quality of the cut, the depth and the number of facets also play a key role in defining the light patterns the diamond will show off.

Use this as another element to consider, but not a definitive test. Brilliance is a very particular subjective characteristic of each diamond.


7. Test for mounting, setting and materials

Genuine diamonds are usually set in metals such as platinum and gold. This is the norm at least, not an imposition. If the materials that make up your diamond jewelry are of poor quality, you may be in the presence of a fake.

There is the case of couples who save on the metal, preferring silver or 14 carat settings, to go for larger stones, so it is not an infallible test either. But certainly, poor quality materials are a red flag.

This by no means applies to antique jewelry. Metals may look completely worn out by the passage of time, but precious gems retain their value intact, if they are real.


8. Testing to read through a real diamond

Another home test, this time more reliable, is the newspaper or read-through diamond test.

In theory, if you place the flat side of the diamond on a sheet of newspaper, you should not be able to read any of the letters. You may see the black spots of ink, but not be able to distinguish their meaning.

This is because the refractive properties of a classic brilliant diamond are considerably high. Light entering the diamond is slowed, bent and distorted inside, due to the angles and facets, making it impossible to read through a genuine diamond.

Although this is not a definitive test, it is a great indication as long as it is done in ideal lighting conditions, with a well-cut and clean diamond.


9. Can you see the point through the diamond?

A simple variant of the full reading test is the diamond dot test. If you take a blank sheet of paper and draw a dot with a pen, place the flat side of the diamond over the dot and look through the tip of the diamond, in theory the dot should not be visible.

Although it is possible that a poorly symmetrical cut may reveal parts of the dot, similar to how it happens with newspaper, it should not be fully visible.


10. Compare a certified diamond against your own for comparison

While we know that not everyone has several genuine diamonds to make extensive contrasts, placing a suspect stone next to an original diamond to compare characteristics can be very enlightening.

Understand that each diamond is unique and we are not trying to compare the overall aesthetics or beauty of the diamond, which is a highly subjective quality. Rather, look at the small details such as sparkle, the amount of fire is balanced and you can notice the sharp angles of the diamond.

Although this test needs good eyes, it is above many others. Similar to how the true color of a diamond becomes more apparent as it is compared to higher quality gems.


How to know if my diamond ring is real?

There is a big difference between testing an unmounted cut diamond and a diamond ring. First of all, the tests must be performed without damaging the precious metal, which is usually much less resistant than the supposed diamond.

To do this, it is most effective to disassemble the stones, this will protect the integrity of the design in most cases. Then, not only the authenticity of each stone is tested, but also the authenticity of the metal, which can also be subject to counterfeiting.

It is best to consult a qualified jeweler with a GIA certification to perform the inspection for you if you have any doubts about the entire piece of jewelry.


Real diamond tester

Although there are many simple methods that can shed a lot of light on the authenticity of your diamond, these methods are far from completely accurate, so how can I know if a diamond is real in a foolproof way?

The answer is very simple: Consult a gemologist, who will be able to determine with complete certainty whether your jewelry is genuine or not.

Reputable gemologists and certified jewelers have special tools like diamond testers and access to laboratory tests that can clear up any doubts.


Magnifying glass

Most jewelers use a 10x magnification loupe to determine a gemstone's inclusions and some details related to facets and cut quality.

The loupe basically allows experts with trained eyes to better appreciate the internal properties of the diamond, giving them a greater ability to determine a poor imitation with the naked eye.


Thermal conductivity probe

The thermal conductivity probe or diamond tester is an electronic device with a metal tip that takes advantage of the diamond's thermal conductivity and electrical conductivity capabilities to differentiate it from other imitations such as cubic zirconia.

Although this tester is extremely reliable in detecting any counterfeit, standard models often fail with some moissanites that may have the same conductivity levels as the diamond. Higher-end detectors have microprocessors capable of detecting moissanites more effectively.

Despite the reliability of the tester, it is necessary for the professional to combine this test with a refractometer.



The refractometer is a specialized tool for testing different stones depending on their light reflecting properties, which works only on cut gemstones.

By placing the table of the gemstone (the flat top) on the refractometer, the refractometer will send a beam of light onto the gemstone which, when reflected, is recorded in a photosensitive cell which will translate the amount of light returned into a number.

The refractometer has a scale of values that helps to determine, according to the number obtained, the type of gemstone being evaluated.


High profile weighing

A high profile weighing for precious gemstones or a diamond scale, as they are also known, is a simple tool that helps determine whether a diamond is counterfeit or not, depending on its weight.

Diamonds of a certain cut and size should be of similar weight to each other.

Some imitations can be up to 50% heavier than a real diamond, others differ by very small percentages, only detectable with a special scale.

Another way to detect a potential scam is to verify that the calculated weight of your diamond matches the weight on your GIA certificate.


Tips for how to know if your diamond is real

There are myriad considerations about authentic gemstones in addition to fakes and synthetics, i.e., minerals and gemstones that are manufactured in a laboratory to simulate the conditions that shape a natural gemstone.

Tips for how to know if your diamond is real

Learning some basic facts about these synthetic materials and main imitators of original diamonds is a good way to avoid a fake.


Synthetic diamonds

Despite popular belief, synthetic diamonds are real diamonds!

Despite being created in state-of-the-art laboratories, there is no difference in the chemical structure of a laboratory diamond that differentiates it from an authentic natural one. They are essentially the same.

how can you tell if a diamond is real or natural? In this case, inclusions are a very good clue to determine the natural origin of a diamond as they are imperfections that are trapped in the diamond as the crystal forms deep in the earth.

To determine if a diamond actually has natural inclusions, a magnifying glass and a trained eye are necessary. Some brilliant diamonds hide imperfections very well and are visible only under microscopes.

In fact, natural diamonds with extremely small imperfections reach very high values in the market. A diamond without external imperfections or inclusions is almost impossible to obtain, hence its high price.


Cubic Zirconia

Cubic Zirconia is usually heavier than a diamond, so in the weight test it will stand out easily. In addition, zirconite does not reflect all the colors of the rainbow once light passes through it but predominantly orange.

Zirconite, in contrast to a genuine diamond, has an intense almost fancy luster and its scintillation and fire patterns are easily differentiated from a diamond upon close examination. A professional should be able to identify them with the naked eye.


White Sapphire

White sapphires are gems that can be passed off as diamonds if worked by an expert. To differentiate a white sapphire from a diamond, look at the stone's scintillation (the light and dark patterns inside).

If you rotate the diamond under the light, you will see that the light and dark patterns do not overlap, nor do they blend together. That is, the dark and light areas in a diamond are well differentiated.

In white sapphire, the light patterns appear more cloudy and the scintillation is not distinguishable in the same way as in a diamond. There does not appear to be a distinct contrast between the black and white areas.



Moissanite is the most problematic stone when it comes to fakes, as it can pass all the easy tests and its value is very low. The best quality ones can even outwit the professional eye if it is not very experienced.

To detect a Moissanite requires a refractometer or special gem microscope, which will allow you to evaluate with total certainty the subtle differences with the diamond.

If only its visible characteristics are available, Moissanite is clearly brighter than a diamond, but its luster is unattractive, looking almost fancy. In addition, they tend to have no inclusions as they are mostly manufactured in laboratories.


White topaz

Another stone that is often used as a diamond imitation is the colorless white topaz. This material is usually much softer than a diamond, so it will not pass the scratch test very well. With a magnifying glass, it is easy to see scratches on the surface, which is uncommon for a diamond.



There are many methods that you can apply at home to get an idea of the authenticity of your diamond, but by analyzing these tests carefully, it is clear that none of them is conclusive and a systematic combination of several methods is required to be sure.

If you feel that you do not have the expertise or the means of how to tell if diamonds are real on your own, the responsible thing to do is to contact a gem expert or reputable jeweler.




  • What's the easiest way to tell if a diamond is real?

    The quickest and simplest way to determine a diamond's authenticity is through the "breath test." Just breathe onto the diamond and check if the fog disperses immediately. If it's the real deal, the fog will vanish right away. This test works because genuine diamonds don't retain heat, unlike fakes.

  • How do you test for diamonds DIY?

    There are several handy DIY methods to test a diamond's authenticity:

    Water Test: Drop the diamond into a glass of water. The real deal will sink to the bottom and shine bright.

    Newspaper Test: Place the diamond over printed text. If you can read the text clearly through the diamond, it's probably a fake. Genuine diamonds refract light, distorting your view.

    Magnification Test: Use a magnifying glass to inspect the diamond for imperfections and uneven cuts. Real diamonds have specific facets and angles that create a unique sparkle.

    Sand Test: Gently rub the diamond on a sandy surface. A real diamond won't show any wear and will scratch the sand without damage.

  • Can you test a diamond with your phone?

    Yup! There are apps available that can help you evaluate diamonds. These apps use your phone's camera and flash to analyze the diamond's brilliance, color, and inclusions. They provide a quick and convenient assessment, though they may not be as accurate as more traditional methods.

  • How to tell if a diamond is real with a UV light?

    Ultraviolet (UV) light can be useful for spotting fakes. Genuine diamonds often exhibit weak blue fluorescence when exposed to UV light. However, keep in mind that some treated diamonds may react differently. So, it's recommended to combine this test with others for more conclusive results.

  • How do you test a diamond with light?

    The light performance test, aka the "sparkle test," involves observing how the diamond interacts with light. Place the diamond on a flat surface, making sure it's clean. Then, use a powerful flashlight and shine the light directly onto the stone. A real diamond will create a bright sparkle and disperse the light into various colors.

  • Can you test diamonds with a magnet?

    Nah, magnets aren't an effective testing tool. Diamonds aren't magnetic, but that's not conclusive because many fake materials aren't magnetic either. You're better off using the tests mentioned earlier, which rely on the unique properties of genuine diamonds.

1 comment
by Edward Hinojosa on May 15, 2023

I found a diamond, carved into a 3D portrait of a TRex , no one millions of years, has ever seen what I have found, it’s a earring, I’m presuming for a high ranking neanderthal, no joke, I need a professionals eyes to point me in the best direction to , let the world see, what amazing stone it is.


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