How to Tell if a Diamond is Real

Apart from the jeweler’s good word, how do you really know if your diamond is real? And if it’s a passed-on antique, what makes it a true diamond?

How to Tell if a Diamond is Real

You’re expected to doubt value and authenticity given that we’re talking about a purchase worth months of paychecks! But what makes this thing more powerful than its premium price is the meaning behind the form.

Because apart from the material, you know that the diamond symbolizes something beyond its monetary worth. Your future with your bride-to-be begins with this love emblem, and it would be a bummer if she finds out it’s a fake!

Although this isn’t usually the case when you consult a diamond expert, knowing the diamond’s authenticity is an interesting skill that you can do at home!

Here Are Some Tests You Can Do Yourself to Make Sure You’re Getting a Genuine Deal

Fog Test – Breathe on the Diamond

Fog Test

The results may vary depending on the environmental conditions you are in. But basically, you’re going to clean the diamond with a soft cloth to remove any trace of oil and dirt. Then, you would have to place it in front of your mouth. Use a tweezer or hold it between your two fingers, then breathe on it.

The diamond will fog because of the heat and moisture in your breath. If the fog takes a few seconds to dissipate, it could be a fake. However, if it swiftly disappears, the diamond is real. This is because diamonds can conduct heat and thus, disperse heat right away.

Water Test – Drop the Diamond into a Glass of Water

Diamond Water Test


Since diamonds have high density, if you carefully drop one into a drinking glass with ¾ water, it will sink to the bottom. If it floats in the middle or at the surface of the water, then you know it’s not real. Though, this test shouldn’t be enough as a moissanite or a cubic zirconia may also sink if too heavy.

Heat Test – Heat the Diamond and Drop into Cold Water

Diamond Heat Test

The heat test looks like it can cause serious damage in a bat, but if your diamond is genuine, you have nothing to worry about! The real ones are made of the strongest material in the world – so strong – that it can cut through glass and is unresponsive to high temperature.

To do the test, fill a drinking glass with cold water. Hold the diamond with plyers, heat it with a lighter for 40 seconds, then drop it into the glass. A real diamond won’t be affected. If your diamond cracks or breaks, it’s probably made of weaker materials and thus, isn’t a true diamond.

Sparkle Test – Observe the Diamond’s Fire and Scintillation

Diamond Sparkle Test

Now, since a diamond is best known for its sparkle, what better way to test it than with our eyes? The sparkle, namely the brilliance, fire, and scintillation bring magic to the stone.

To test this, hold your diamond under a regular lamp, and observe how the white light bounces off and the colorful light reflects. A true diamond will exhibit incredible sparkle that’s incomparable to the supposed brilliance of a cubic zirconia, for example.

Get Familiar with Lab-Created Diamonds, Simulants, and Other Stones That Look Like Diamonds






Cubic Zirconia

Cubic Zirconia

Cubic zirconia doesn’t bear inclusions, and this alone is a great indicator as diamonds usually possess imperfections that can be seen under a loupe or with bare eyes.

It also gives off an orange tint and is noticeably not as brilliant as a real diamond.



White Topaz

White Topaz

A white topaz can easily get scratched as it’s softer than a diamond. So, if you see scratches on the surface, it could most likely be a white topaz or a poor cut diamond with bad polish. And you wouldn’t want either of those.



White Sapphire

White Sapphire

Though sapphires are usually known for their blue, red, and other colors, there are also white ones that are sold as diamonds.

The difference is stark when you compare a white sapphire and a diamond side by side because the former will look blurry as opposed to the superb brilliance and contrast of the dark and light parts of a diamond.





No other stone can beat the moissanite as the ultimate fake diamond. You can test the stones above yourself, but this one is more complicated.

You would have to perform an electrical conductivity test. But still, the results are tricky, so with this one, we leave it for the professionals to figure out.



Lab-Created Diamond

Lab-Created Diamond

I’m not against lab-created diamonds as they’re still diamonds. It’s just that they are grown in the lab, unlike natural diamonds created in the earth’s mantle.

They have the same molecular components so that the only way of knowing – like the moissanite – is to have an expert run a conductivity test.



Real Diamond

James Allen Diamond  

This is what a real diamond looks like in 20x magnification. Not just any diamond, but one with an Excellent Cut and a True Hearts and Arrow pattern. Click the image to view the diamond’s brilliance in high definition!

Use a Diamond Loupe

Diamond Loupe


Let’s say, you’ve read a handful of articles about diamonds and knew a thing or two about the 4Cs. If you have a good magnifying glass at home, you’ll be able to have a closer look at the diamond’s composition, clarity, and scintillation.

You’ll know it’s a fake diamond like cubic zirconia if it’s too flawless as natural diamonds typically bear microscopic to visible flaws! If you don’t have a loupe or you’re not 100% confident on the tests you performed, you can always rely on a diamond expert!

Consult Appraisers or Diamond Grading Labs

Diamond Grading Certificate


While there’s pride in knowing the authenticity of your diamond without professional help, the best way is a guaranteed approach! Top gemological labs like GIA and AGS have world-class equipment to identify fakes and simulants.

With a trusted appraiser and the said grading authorities, no questions asked, you’ll be assured of your diamond’s legitimacy. Having a diamond with a GIA or AGS grading report is an instant badge of honor and the ultimate form of assurance.

Buy from Reputable Online Diamond Shops

James Allen

You may contact a private appraiser or the top grading labs to put a stamp of approval on your diamond. But if you haven’t bought yet, there are reliable diamond stores that offer diamonds graded by GIA and AGS. With this, there’s no need to check the stone’s authenticity, rest assured you’ll be getting a true diamond.

Of course, we don’t solely base our decisions on the grading certificate, reputable shops like James Allen also provide diamond display technology that will let you inspect your choice through 360° HD videos and 40x zoom!

The Takeaway


Let me be clear that none of the tests above are conclusive and the most efficient way is to consult a trained eye or buy from reputable shops.

I know it’s self-assuring and a little fun to run these experiments at home, plus it’s safe and easy! But if your pending proposal is on the line, leave it to the experts, they still have the last say if your diamond is real or not. 🙂

Should you have any question, please feel free to comment down below. Or email me – my advice is always free!