7 Tests to Tell if a Diamond is Real or Fake

Can you tell whether a diamond is real or fake? Now I’m not saying to make a mad dash to all your jewels and second guess their authenticity (although you may want to after this lesson), but knowing the difference between genuine and synthetic diamonds is a helpful asset to have, for many reasons.

You may be hunting the antique fairs, second guessing a recent gift, or simply want to tell if Cynthia’s 3 carat rock is actually worth bragging over.

diamond is real or fake

A knowledge of jewelry is always a vital tool for a lady to keep in her back pocket, particularly when it comes to the ever prized diamond.

Here are 7 tests that you can easily perform at home to see if you’re in possession of a real or fake diamond. Fingers crossed that you get the answer you want!

1. Fog Test

An immediate test you can try is the fog test. This simply involves breathing over the diamond so that it fogs up, as you would to a pair of glasses you’re cleaning. If there is visible fog left on the diamond than it is likely a fake. Genuine diamonds will disperse heat rapidly so will not easily leave fog on the surface.

 2. Reading Test

Place your diamond over newspaper or magazine text. If you’re able to read or even see the letters through the stone then you have a fake. Diamonds refract light so much that it shouldn’t be possible to see anything through the stone. You can also perform this test if the stone is mounted, just look through it to see if you can see the mounting. If you can see it then it’s synthetic.

3. Water Test

Drop your stone into a glass of water. Diamonds are high density so they will naturally sink right away. If they float or only sink part way down, then you don’t have yourself a diamond.

4. Scratching Test

Try scratching the diamond with a piece of glass or sandpaper. Diamonds are the hardest naturally occurring substance on Earth, so practically nothing should leave a mark on them. If no mark is left behind, then you likely have yourself a genuine diamond. I only recommend this test if you’re not attached to the stone as it will become damaged if it turns out to be a fake.

5. Reflection Test

Hold your stone up to the light. Internally you should only see shades of grey and white reflected within a diamond. If you see rainbow colors within the stone it’s probably synthetic. However, outside the stone diamonds can reflect rainbow colors, this is known as fire.

6. Setting Test

If your stone is in a setting,then inspect it to see its quality. The quality of the setting will typically match the quality of the stone. You wouldn’t mount such an expensive diamond in a cheap setting or vice versa put a cheap stone in such an expensive setting. So for example, if it’s a larger stone set in sterling silver then it’s not likely to be a real diamond. It would more likely have a gold or platinum setting.

7. Perfection Test

Although diamonds are one of the most beautiful stones on earth it’s very rare that they are perfect. Isn’t that the case with all beautiful things. If you look at a stone and it literally has no imperfections, then it’s most definite not a natural diamond. You may need a loupe, aka a magnifying glass to properly conduct this test, but they are easily obtained from a jeweler. They probably will let you just borrow theirs if you ask.


These tests are all easy at home tests, but some high quality synthetics can be more tricky to detect. If you still have your suspicions or need to know for certain, I highly suggest taking your stone to a qualified gemologist so they can confirm for sure.

HOMEWORK: If you have a diamond on hand take a look and see if the tests hold up. Hopefully they will!


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Photo Credit:Popsci.com