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How to Tell if a Diamond is Real


How to Tell if a Diamond is Real

How to tell if a diamond is real


A combination Diamond/Moissanite tester will quickly indicate whether a diamond is real or not.
Diamond tester

How to Tell if a Diamond is Real

To know how to tell is a diamond is real or not can save you much hardship and financial loss when purchasing a new stone for yourself or a loved one. There are many fakes and out there and nearly just as many people trying to sell them. It’s always best to have a stone examined by a trusted jeweller, but failing that, here are a few tips that can provide you with a little confidence in your decision.


1- Firstly, ask the seller to prove its authenticity. Every diamond should have a certificate that grades the diamond’s authenticity (AGSL, LGP, GIA, PGGL), or the seller should provide for an independent appraiser who is affiliated with a professional organisation if you request it. If you’re buying from the internet, this is especially important. Bear in mind however, that although a certificate may suggest that the stone is real, it is not imitation proof.

2- A diamond does not reflect the spectrum (rainbow colours), unless it’s of low quality. Real diamonds reflect different shades of grey.

3- Breath on it. Exhale on the stone as if you were cleaning a pair of glasses. As heat disperses quickly through a diamond, the fog should dissipate near immediately.

4- Glare through the stone. Diamonds bend the light that passes through them (they have a high refractive index). Glass and quartz sparkle less as they have less of a refractive index. A good way to test this is to place the stone on some newspaper (providing it has not been mounted). Should you be able to read any of the text or even see black smudges through the diamond, then it probably isn’t real. If the diamonds is cut disproportionately however, the ink will still be visible. If the diamond is mounted, it should not be possible to see the bottom of the stone when looking from the top.

5- Check how the stone is mounted. Is it set in real gold or platinum (stamped accordingly). If it is stamped “C.Z.”, then the centre stone will be an imitation.

6- Be aware of silicon carbide (Moissanite). Even some jewellers find it difficult to tell these apart from diamonds. Should you see any sign of double refraction i.e. double vision, when viewing the star facets on the top side of the stone, then there is a good chance that the stone is silicon carbide.

7- Use a microscope. When held top down under a microscope and tilted side to side, should you see any orange flashes then the diamond is fake.

8- Use its weight. Carat or gram scales are readily available on the internet. Weigh the stone and compare it with the relevant scale.


Fake diamonds tend not to be able to scratch sandpaper. Be wary however of testing it by scratching it on other hard surfaces. Although it will not scratch, it may chip as diamonds are very brittle.

If you take the stone to be reviewed independently, make sure it never leaves your sight as it may be switched with a fake.

Only a registered certificate can prove a diamond is real to 100% certainty. When buying a so called diamond from any source other than from trusted high street jewellers, you will always be taking a risk.

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