How to Tell if a Diamond is Real

Did you know that 80% of people struggle to distinguish real diamonds from fake ones? You don’t need to be a jeweler or an expert to figure it out. While technology has made it easier to craft convincing imitations, the good news is there are simple methods you can use to tell if a diamond is genuine. In this guide, you’ll discover practical, easy-to-apply tests that will help you quickly determine the authenticity of a diamond. Keep reading to unlock the secrets that jewelers use, and even learn a few tricks they might not tell you about!

1. The Water Test – Simple Yet Effective

Let’s start with the easiest one, the water test. If you’ve never heard of this, you’ll love how low-effort it is. All you need is a glass of water and the diamond in question. Drop the stone into the water. A real diamond will sink because it has high density, while a fake one will likely float or stay just beneath the surface. It’s as simple as that!

Why does this work? The density of a real diamond (about 3.5–3.53 g/cm³) is much higher than most imitations like glass or cubic zirconia. So, by simply observing the sinking behavior, you can make a quick assessment without any fancy tools.

2. The Fog Test – Breathing New Life into Verification

Here’s another test you can perform almost anywhere. Hold the diamond between your thumb and forefinger and breathe on it, just like you would if you were fogging up a mirror. If the diamond is real, the fog will dissipate almost immediately. Why? Diamonds have excellent thermal conductivity, so they disperse heat rapidly, causing the condensation to disappear quickly. On the other hand, a fake diamond, like cubic zirconia, will stay fogged for a few seconds longer.

However, it’s crucial to note that while this test works well on natural diamonds, it may not be as effective with lab-grown diamonds, which share similar properties to natural ones.

3. Check the Setting and Mount – What’s Holding the Diamond?

One of the best indicators of whether a diamond is real is how it’s mounted. Real diamonds are often set in high-quality metals, such as platinum, white gold, or yellow gold. Take a close look at the setting. Does it have any stamps indicating the type of metal? For example, real gold is typically marked with numbers like 10K, 14K, or 18K, which refer to the karat purity of the gold.

If the diamond is mounted in a cheap, thin metal or a clearly low-quality setting, there’s a high chance it’s a fake. Jewelers don’t typically waste precious metals on fake stones. Moreover, check for small engravings or laser inscriptions near the girdle (the outermost edge) of the stone. These are additional signs of authenticity.

4. The Loupe Test – Look for Imperfections

To get more technical, grab a jeweler’s loupe, a small magnification tool used to inspect stones. Real diamonds often have imperfections known as inclusions, whereas fake ones are usually flawless. The presence of inclusions or slight blemishes can indicate that you’re looking at a genuine, natural diamond.

While cubic zirconia or synthetic diamonds may appear perfect under magnification, real diamonds have these tiny imperfections, which are often impossible to see with the naked eye. This test can be particularly useful for identifying older diamonds, which may have more visible flaws due to the natural formation process.

5. The Scratch Test – Hardness Isn’t Just a Myth

Here’s a myth-busting test that still holds true: diamonds are the hardest natural material on Earth, ranking 10 on the Mohs scale of hardness. This means that they can scratch almost anything, and nothing can scratch them—except another diamond.

To test this, take a piece of glass or another relatively soft material, and carefully try to scratch it with the diamond. If the stone scratches the glass, it’s likely a real diamond. But if it leaves no mark, you’re probably dealing with a fake.

6. Use a Diamond Tester – Bringing Technology to the Rescue

When in doubt, technology comes to the rescue. A diamond tester is a handheld device that can test the thermal and electrical conductivity of a stone. These are widely available and easy to use. Just place the probe against the stone, and the device will give a reading indicating whether the diamond is real or not. Real diamonds will conduct heat well, while imitations like cubic zirconia or glass will not.

If you’re serious about confirming the authenticity of a diamond, investing in a diamond tester might be worth it. These tools are commonly used by professionals and can provide definitive results within seconds.

7. UV Light Test – Shine Some Light on the Truth

Did you know diamonds often fluoresce under ultraviolet (UV) light? This is an interesting test because most diamonds will emit a blue glow under UV light. However, not all real diamonds will fluoresce, and some fake diamonds may also exhibit similar glowing effects. So while the UV light test isn’t foolproof, it’s another handy tool to have in your arsenal.

8. Weigh It – Real Diamonds Are Heavier

Finally, you can use weight as an indicator. Real diamonds are heavier than most of their fake counterparts. If you have access to a scale and a known real diamond of the same size, weigh both stones. The real one will generally be heavier, as cubic zirconia, for instance, is about 50% heavier than a real diamond of the same size. Comparing weight might seem like an advanced technique, but it’s actually one of the most straightforward ways to confirm the authenticity of a diamond.

Conclusion

Determining whether a diamond is real doesn't have to be a daunting task. From simple water and fog tests to more advanced methods like diamond testers and UV light, there are plenty of ways to check for authenticity without needing a professional. Remember, real diamonds will have tiny imperfections, excellent conductivity, and specific physical properties that imitations simply can’t replicate. Now that you’re equipped with these tips, you can confidently assess diamonds like a pro!