How Can I Tell if a Diamond is Real?

If you are looking to buy a new diamond, then you should make sure that it comes with a GIA or AGS certificate, and that the diamond that you get matches exactly what is described on the certificate. If you already have a diamond, though, then you may not have a certificate with it. Perhaps it was given to you as a gift, or you inherited it. Whatever the reason, you have no idea of the providence or authenticity of this diamond, and now you want to get an idea of what it might be worth. Here are a few tips that will give you an idea of whether a diamond might be real or not. If the tests indicate that a diamond might be real, then you should have it properly appraised to confirm that for sure.

Real vs Fake Diamonds

If you’re not familiar with a diamond’s make-up, then it’s easy to make a mistake and think that a diamond is real when it’s actually just moissanite or cubic zirconia. These look similar but are more fragile and less valuable.

It’s easy to test whether a diamond is real or not, though. If the diamond is not in a setting, then you can simply drop it into a glass of water. If the gem sinks, then it is a diamond. If it floats to the surface or bobs just under the surface, then it’s a different kind of gem. Real diamonds are very dense, so will sink.  Of course, if the diamond is already set in a ring or other piece of jewelry, you won’t be able to do the test.  There are other tests, though.

The Fog Test

Th fog test is very simple to perform. Simply hold the diamond between your fingers and breathe out onto it. You should see a light fog form on the diamond as the moisture in your breath condenses. If the fog dissipates immediately, then this means that the diamond is real. If, however, the fog takes longer to disperse, then it is probably fake. Diamonds conduct heat quite efficiently, which means that they will disperse heat rapidly, and that’s why the fog should go away fast. This test isn’t completely guaranteed to work – and it will work better if the diamond hasn’t been handled/warmed up recently.

Check the Setting

If the diamond is already in a ring, then the setting and mount that was used for it will give you an idea as to the authenticity of the diamond itself. Diamonds are expensive, and a real one is likely to be set in very high-quality jewelry. If you have a white gold, yellow gold or platinum ring, it is probably made with a real diamond. Settings such as side-stone, pave and halo style are more likely to be used with good stones such as diamonds.  If it is a relatively new piece of jewelry, then it will have notes, such as 10K, 14K, 18K, PT or Plat on them. Alternatively, European jewelry might be marked with 585,770,900 or 950 – these are all indicators of high-quality gold or platinum. A piece of jewelry that has C.Z. marked on it is made with cubic zirconia, not real diamonds.

UV Light

If you have access to a UV light, then you can shine it on the diamond. Most diamonds will glow blue under UV light, so if it does glow then it is probably real. However, this test does not “prove a fake” because not all diamonds glow blue. It is worth getting an expert to test the stone properly.


Destructive Testing With Heat

Diamonds are very strong and will not respond to heat at all. If you heat a stone under a lighter for 30-40 seconds, then drop it into cold water, nothing will happen. If you do that to cubic zirconia or glass, then it will crack and shatter. Therefore, this is a test that you should perform only on a stone that has no sentimental value for you. Diamonds are incredibly strong and disperse heat quickly. They will not be damaged by the rapid changing in temperature.

Newspaper Tests

The way that diamonds refract light is something that is measured in terms of ‘brilliance’. Cubic Zirconia and other imitation diamond types do not refract light quite as well as real diamonds, and this will show when you try to ‘read through, the diamond.

To test how well a diamond refracts light, place the stone, flat side down, onto a piece of newspaper in an area that has lots of letters. Make sure that the area is well-lit, and that there is nothing casting a shadow over the diamond. If you can read the letters through the diamond, then that means the diamond is fake. A real diamond will have lots of facets that refract the light so that it goes in different directions. You should not be able to see clearly, straight through the diamond to look at the letters on the paper.

This particular test works best on diamonds that are loose. If your diamond is already set into a piece of jewelry then you may not be able to do this test properly. You can still do refraction tests, though – even just holding the diamond up to a lamp will give you an idea – if it reflects white light well, and provides a nice sparkle, then it is probably real. Diamonds will reflect colored light incredibly well too. Cubic zirconia will not produce the same kind of impressive sparkle.

If you’re not sure if a diamond is real then you should take it to have it examined by an expert, because they will be able to offer much more detailed insights. A qualified gemologist from Elizabeth Diamond Company will have access to specialist equipment including thermal conductivity probes and specialist magnifying devices that will help them to identify the qualities of the stone that they are examining. If you have reason to believe that a diamond is real, then you should have it examined and appraised.