How to Tell if A Diamond Is Real: A Comprehensive Guide

"Diamonds are a girl's best friend." -Marilyn Monroe.

And just like friends, it is important to identify a real diamond.

Planning a perfect proposal? Want to impress your mom on Mother’s Day? Or simply want to spoil yourself? Buying a diamond can be one of the best decisions you ever made.  However, it’s important to ensure that you’re not getting duped into buying a fake. 

Believe it or not, experts say that 1 in 5 diamonds on the market is either fake or lab-grown. And to be honest, it’s quite chilling to know that, especially when we’re talking about something that costs really high.

Diamonds are forever! They portray beauty, power, luxury, and loyalty, which is why it’s a shame that there are so many fakes out there. With the rising number of synthetic diamonds, finding the real one is more stressful than it should be.

Just try to think about it. You surely would love to know if that ring of engagement that you have been wearing for many years is real. And what about that heirloom from grandma? Is it worth more than you think? In this guide, we’ll walk you through 14 diamond testing methods so you can confidently spot a fake.

A Little Background Of Diamonds - Nature's Masterpiece

What exactly makes diamonds so precious? 

Owning diamonds is indeed associated with great luxury because these are extremely rare. They look astonishing and are highly durable. There’s no denying that diamonds are more than just beautiful gemstones. They are timeless.

But the real magic lies in their origin story.

Surprisingly, diamonds are born deep within the Earth’s mantle. They undergo intense heat and pressure over millions of years, creating their unique crystal structure. Hence, diamonds are the hardest natural substance on Earth. Their journey from deep underground to a sparkling piece of jewellery adds to their mystique.

However, advanced technology now makes materials like cubic zirconia exactly like a diamond. That's exactly why learning how to tell if a diamond is real or a dupe has never been more important. 

How To Tell If A Diamond Is Real Or Fake? Reliable Ways

As much as the beauty of diamonds is appreciated, it is a challenge to identify the difference between a real and a fake stone. In the mind of every diamond lover, there is a question that always repeats: “How can you tell if a diamond earring is real or fake?”

Here’s Emily’s answer: 

While celebrities and rappers love flaunting diamond-encrusted luxury watches, bracelets, and necklaces, remember, even the biggest names can be fooled by fakes. Don’t let that be you.

Here are some tried-and-true ways to verify if your gemstone is the real deal. The best part is that some of the below tests can be performed easily at home, without specialised instruments. 

1. The Weight Check

How to tell if a diamond is real at home often starts with simply observing weight. Ever wonder why some diamonds feel hefty? That’s because real diamonds are incredibly dense compared to most imitations.

The difference in weight stems from the atomic structure of each material. Diamonds are composed of tightly packed carbon atoms, making them different from synthetic stones. 

This difference is especially noticeable when comparing stones of similar dimensions. Wondering how to tell if a diamond ring is real? Make sure you weigh the diamond. If it feels unusually light for its size, that's a red flag.   

Here’s how to test it:

1. Ideally, use a carat scale, a precise tool used by jewellers.

2. Weigh the suspected diamond and note its value.

3. Compare it to the weight of a replica stone of the same dimensions (e.g., cubic zirconia or glass).

4. If your stone's weight falls significantly outside the expected range, it's likely a fake.

Pro Tip: Don’t have a reference for diamond stone weight? A quick Google search for diamond weight charts can help you compare dimensions with expected carat weights.

In the meantime, try our round diamond size chart below to understand the size of each diamond shape. You can find similar charts for Princess, Cushion, Oval, and other diamond cuts online. 

2. The Sparkle Test

Diamonds may look like glass, but they behave nothing like it. A real diamond’s shine and reflectivity set it apart from synthetic alternatives. 

Diamonds are celebrated for their exceptional ability to reflect light, creating dazzling white flashes and a beautiful spectrum of colours. By contrast, imitations often appear duller or have a rainbow-like sparkle.

Here are three elements to consider:

• Brilliance: This refers to the intense white light reflected from the diamond's surface. A well-cut diamond acts like a tiny mirror, maximising the amount of light that bounces back to the viewer's eye. 

• Fire: This is an effect experienced by observing a diamond stone. It explains how light passing through the diamond is refracted, producing rainbow colours. 

• Scintillation: This is the sparkle or twinkle seen in the diamond. When the light source or the viewer moves, a beautiful combination of light and shadow appears.

3. Check Our Jewellery Collection

   The Sink or Swim Test

The water test is a quick and easy way to determine if a diamond is real. Since diamonds are denser than water, they should sink. The test is simple to perform at home and doesn’t require expert help. 

Here’s how to do it:

1. Fill a clear glass with water.

2. Gently drop the diamond into the water. (This test won't work with mounted stones as the setting's weight will affect the result).

3. Observe what happens. A real diamond will sink immediately to the bottom. If it floats or hovers, then it likely is a fake.

Caution: This test is not foolproof. Certain synthetic stones, like moissanite, share similar densities and may sink as well. It's best used as a preliminary test alongside other methods. 

4. The Breath Test

The fog test utilises diamonds' unique thermal properties. Diamonds are excellent conductors of heat. They disperse heat rapidly, meaning they don’t retain fog on their surface for long. This makes it easy and effective to distinguish between real and fake stones.  

Here’s how you can perform the fog test at home:

1. Hold the diamond close to your mouth and breathe on it, creating a light fog on its surface, just as you would on a mirror.

2. Observe how quickly the fog disappears.

3.  On a real diamond, the fog will disappear almost instantly because the diamond quickly disperses the heat.   

4. If the fog lingers for a few seconds, it’s probably a fake.

This test is particularly useful for determining whether a diamond necklace is real or fake, provided the stones are loose. It’s also non-destructive, making it safe for valuable stones.

5. The Flashlight Test

The reflectivity test dives deeper into how a diamond interacts with light. 

Genuine diamonds can reflect light inside and outside the stone, producing an incredible amount of sparkle that is often unmatched by many fakes. This is because the diamond's high refractive index allows its cut to reflect light beautifully.

Here’s how you can conduct the reflectivity diamond testing: 

1. Shine a flashlight directly onto the stone.

2. Make sure to pay attention to how the reflections appear. The true nature of diamonds is such that they can reflect light, producing bright white and red-blue colours. 

3. Fakes often appear dull or overly colourful.

4. Turn the stone and examine its sparkle from different angles.

Note: Experts say that it is a good way to tell if a black diamond is real.

6. The Heat Conductivity Test

Use the heat conductivity test if you are wondering how to tell if a diamond is fake or real. 

Diamonds are known for being the best heat conductors. If your stone isn’t a good conductor of heat, it’s a fake.  Here’s what you need to do check for it:

1. Use a thermal conductivity meter, which can be found online or at some jewellery stores.

2. The meter measures how quickly the stone conducts heat.

3. A real diamond will disperse heat rapidly, registering a high conductivity reading.

4. Simulants like cubic zirconia will retain heat longer, resulting in a lower reading.

5. The Scratch Test

Diamonds are one of the hardest substances on Earth, having a rating of 10 on the Mohs Hardness Scale. They are capable of scratching almost any material, including glass. That’s why this test is so effective. 

Here are the steps to perform the scratch test on a diamond:

1. Select an edge of the diamond for testing.

2. Gently scratch a piece of glass or another hard surface.

3. Observe the result. If the surface is scratched, the diamond is likely real.

It’s a risky move (don't try this at home!)

This test carries risks of damaging both the diamond (especially if it’s set in jewellery). It is generally not recommended for valuable gems, as professional evaluation is safer and more reliable.

However, many simulants are also quite hard and could potentially scratch glass, making this test a little unreliable and risky. 

8. The Glow Test

Did you know some natural diamonds give off a bluish glow under ultraviolet (UV) light? This glow, known as fluorescence, can be a helpful clue when trying to determine if a diamond is authentic. 

While it’s not a definitive test (as not all genuine diamonds fluoresce), it’s a quick and fascinating way to assess your stone at home. Simply:

1. Use a blacklight or any UV light, and create a dark environment for the test.

2. Position the diamond under the UV beam and carefully observe.

3. Many natural diamonds will emit a faint to noticeable blue fluorescence, though the intensity can vary.

Note: Fluorescence is more common in natural diamonds and can range from very faint to strong. However, don’t panic if your diamond doesn’t glow - this trait is absent in some completely authentic diamond stones.

9. Professional Appraisal 

When you’re unsure about your diamond’s authenticity, there’s nothing quite like getting it professionally appraised. Expert gemologists have the tools and know-how to evaluate your diamond with precision, leaving no room for doubt.

These professionals can spot details you might miss at-home tests, offering a clear, accurate analysis. Their expertise takes the guesswork out of the process, giving you peace of mind.

Organisations like the Gemological Institute of America (GIA) or the International Gemological Institute (IGI) are the gold standard when it comes to certification. A diamond certificate from these reputable sources covers essential details like:

• Cut

• Clarity

• Carat Weight

• Colour

Not only does this certification confirm your diamond is the real deal, but it also increases its resale value, making it a smart investment. Whenever you’re buying a diamond, be sure to ask for certification; it’s your ultimate proof of authenticity.

10. The Dot Test

The dot test is a simple yet clever way to check if your diamond is real. It uses the high refractive index of a diamond to differentiate it from fakes. Real diamonds bend light so intensely that objects beneath them either vanish or appear distorted, unlike most imitations.

To perform the dot test, simply: 

1. Draw a small dot on a piece of white paper.

2. Place the diamond flat side down over the dot.

3. Look directly through the diamond.

4. If the dot disappears or appears distorted, the diamond is likely real.

Note: This easy home method is a great first step in confirming your diamond's authenticity. Keep in mind that it works best with loose stones.

11. Electrical and Thermal Conductivity Tests

When it comes to advanced methods for identifying diamonds, electrical and thermal conductivity tests are highly reliable. These tests are especially effective for distinguishing real diamonds from moissanite, a common diamond substitute.

How to perform electrical and thermal conductivity tests on diamonds:

1. Obtain a dual-mode tester designed for measuring both thermal and electrical conductivity.

2. Place the tester’s probe on the surface of the gemstone.

3. Record the readings.

4. Diamonds conduct heat exceptionally well but do not conduct electricity. Moissanite, on the other hand, conducts electricity, which helps differentiate it from a real diamond.

5. Compare the results to standard values for diamonds.

Note: These tools provide immediate, precise readings, making them invaluable for jewellers and diamond enthusiasts. Unlike visual tests, conductivity measurements leave little room for error, ensuring a higher degree of certainty in your results.

12. The Magnifying Glass Method

Under magnification, natural diamonds reveal unique inclusions and blemishes that synthetic stones often lack. These internal features are like fingerprints, confirming the diamond’s authenticity.

Here’s how to perform microscope and loupe examinations on the gemstone:

1. Use a 10x jeweller’s loupe or a gemological microscope.

2. Examine the diamond for tiny imperfections, such as mineral inclusions or feathering.

3. Real diamonds typically have some level of natural imperfection, while fakes appear flawless.

This professional technique is highly reliable and offers a fascinating glimpse into the diamond’s formation history.

13. Magnetic and Sparkle Tests

Diamonds are non-magnetic, and their sparkle is unmatched by other gemstones. These simple tests provide quick clues about authenticity. Simply:

1. Hold a strong magnet near the diamon.d

2. Look for a reaction. If the diamond is real, then there should be no reaction.

3. Examine the stone’s sparkle under direct light.

4. Real diamonds display sharp white light reflections (brilliance) and subtle rainbow flashes (fire).

These tests are easy to conduct and highly effective in identifying imitations with noticeable flaws in sparkle or magnetism.

What to Do If You Suspect a Fake

While vacationing in Mexico, an Ontario couple bought a $4,176 diamond engagement ring. The jewellery seller promised paperwork proving the diamond's quality, but the couple never received anything. 

Back in Canada, an appraiser said the diamond was phoney and worth only $50. That must’ve been a shock!

After the merchant objected, their bank reinstated the charge. After a lengthy investigation, the bank repaid the couple. This instance highlights how perilous buying pricey jewellery abroad is.

Discovering that your diamond might not be genuine can be unsettling, but there are actionable steps you can take to ensure clarity and peace of mind.

If any of the at-home tests raise doubts, your next step should be to consult a reputable jeweller, trusted website, or certified gemologist. They’ll provide you with an accurate evaluation, eliminating any guesswork.

For peace of mind, consider purchasing reliable diamond-testing tools like thermal and electrical conductivity testers. These devices are excellent for quick assessments, particularly for differentiating between real diamonds and common substitutes.

In Conclusion: Enjoy The Allure of Real Diamonds

Owning a real diamond is an investment in beauty and timeless elegance. Whether you are investing for yourself or passing it down to your daughter, it is important to understand how to tell if a diamond is real or a dupe. 

If you have a diamond you are unsure about, use these tips to test its authenticity. And if all else fails, remember that a professional jeweller is just a call away.

Remember, a little effort goes a long way in ensuring you’re holding the real deal!