How to Spot a Real vs Fake Diamond

At Diamond Ateliers, we know that buying a diamond ring can feel like navigating a maze. Whether it’s your first time or you’re a seasoned pro, it’s natural to wonder how you can be sure you’re getting the real deal. Luckily, there are a few practical ways to test a diamond’s authenticity—and we’re here to walk you through them, step by step.

From simple at-home methods to professional lab certifications, let’s explore how to tell if a diamond is truly authentic.

The Dot Test: A Quick Home Method

If you’re looking for an easy way to get started, the dot test is a handy trick. Here’s how it works:

1. Grab a piece of white paper and draw a small dot.
2. Place the diamond flat side down on top of the dot.
3. Look directly through the diamond.

See our founder Don perfomring the dot test himself in less than 20 seconds. You can too!

What Happens with a Real Diamond?

Real diamonds have an incredible ability to bend and scatter light, all thanks to their high refractive index. When you place a diamond over a dot on a piece of paper, this light-bending magic makes the dot disappear. It’s one of the reasons diamonds sparkle so brilliantly—they don’t let light pass straight through but instead bounce it around in dazzling ways.

On the other hand, imitation materials like cubic zirconia or glass just don’t have the same light-scattering skills. When you perform the same dot test with these lookalikes, you’ll likely still see the dot clearly through the stone.

Real Diamonds Includes Lab Diamonds

Not every “real” diamond comes from the earth. Lab-grown diamonds are just as authentic as their natural counterparts. They’re chemically and optically identical, which means they’ll pass the dot test with flying colors. So, while this test can confirm whether you’re dealing with an actual diamond, it doesn’t distinguish between natural and lab-grown stones (both of which are equally real).

The Dot Test is Not Foolproof

Certain imitation materials, like moissanite, are exceptionally good at mimicking a diamond’s refractive properties. Moissanite, in particular, can bend light in ways that make the dot disappear, just like a real diamond. This means the dot test, while helpful, isn’t a foolproof method for identifying a diamond.

So, while the dot test is a fun and easy starting point, it’s just that—a start. For true certainty, professional testing or certification is the way to go.

Other Methods to Verify Diamond Authenticity

While the dot test is a great starting point, there are several other ways to verify if a diamond is genuine. These methods range from simple, DIY tricks to professional-grade assessments, each offering unique advantages and considerations. Here’s a closer look at how you can confirm a diamond’s authenticity.

The Fog Test

The fog test is a simple way to check a diamond’s authenticity. Hold the diamond between your fingers, breathe on it to create fog, and observe how quickly it disappears. Real diamonds dissipate heat quickly, causing the fog to vanish almost instantly. However, this test isn’t foolproof—humidity and other environmental factors can affect the results. Plus, some imitation stones like moissanite may also clear the fog quickly, making it an unreliable standalone test.

The Water Test

For the water test, fill a glass with water and drop the loose diamond in. Real diamonds are denser than most imitation stones, so they’ll sink to the bottom. This test doesn’t work if the diamond is set in jewelry, as the metal setting can affect the results. Also, high-density imitation stones like moissanite may sink as well, making this test inconclusive in some cases.

Magnification Inspection

Using a jeweler’s loupe or magnifying glass, inspect the diamond for natural imperfections known as inclusions. These tiny, unique flaws are often present in real diamonds, acting as a natural fingerprint. However, this method requires a trained eye—without experience, it can be difficult to distinguish real inclusions from synthetic flaws. Additionally, lab-grown diamonds may also have inclusions, so this test won’t differentiate them from natural diamonds.

Thermal Conductivity Testing

Thermal conductivity testing measures how efficiently a stone conducts heat. Diamonds are excellent heat conductors, so this test works well to separate diamonds from fakes like cubic zirconia. However, it can be tricked by moissanite, which has similar heat conductivity properties. To improve accuracy, it’s best to combine this test with electrical conductivity testing.

Electrical Conductivity Testing

This test measures a stone’s ability to conduct electricity. While diamonds are poor electrical conductors, moissanite is highly conductive, making this test effective at identifying moissanite. However, this method requires specialized equipment and is typically only available through professionals, making it impractical for at-home use.

UV Light and Fluorescence Testing

When exposed to UV light, many diamonds emit a blue fluorescence, which is rare in imitation stones like cubic zirconia. This test can help identify real diamonds, but it’s not foolproof. Not all diamonds fluoresce, and some fake stones can mimic this effect. To get the most reliable results, it’s best to use this test in conjunction with others.

How Professionals Authenticate Diamonds

When it comes to determining whether a diamond is authentic, professionals rely on science and advanced tools that go far beyond any home test.

The Gold Standard: Certification

The most reliable way to ensure your diamond’s authenticity? Get a grading report from a trusted organization like:

• GIA (Gemological Institute of America): The industry benchmark for diamond grading.
• IGI (International Gemological Institute): Another highly respected name in the field.

These certifications confirm the diamond’s authenticity and provide a detailed breakdown of its 4Cs—carat, cut, clarity, and color—so you know exactly what you’re getting.

How Labs Ensure Accuracy

To guarantee precision, labs like GIA and IGI use a combination of advanced tools and methods to thoroughly examine each diamond. These include:

• Thermal Conductivity Testing: To confirm the diamond’s heat conduction properties.
• Electrical Conductivity Testing: To distinguish moissanite from diamonds.
• Magnification Tools: To inspect internal inclusions and unique characteristics.
• UV and Spectroscopy Testing: To analyze light absorption and fluorescence.

Once the examination is complete, the lab generates a unique certificate for each diamond, which includes a specific report ID. This ID can be verified against the lab’s database, allowing you to cross-check the authenticity and details of your diamond with absolute confidence. With this certification, you’re not only assured of the diamond’s quality but also its origin and authenticity.

We’ve Got You Covered

At Diamond Ateliers, we take the guesswork out of your diamond-buying journey. Every diamond we sell comes with a certificate of authenticity, so you can shop with confidence.

Still have questions? Our team is here to guide you through the process, from choosing the perfect diamond to understanding its certification.

Or, if you’re already picturing your dream ring, let us help you design something truly one-of-a-kind. Whether it’s personal engravings, unique settings, or creative accents, we’ll bring your vision to life.

Reach out to us today, and let’s make your diamond story unforgettable.