How to Tell If a Diamond Is Real

How to Tell If a Diamond Is Real

Date Icon 25 September, 2025

Everyone dreams of owning diamond jewelry—but what if you aren’t sure whether you already do? Maybe you have a necklace that you got secondhand or a ring of uncertain origin. Wherever the piece came from, you should know whether or not the gemstone is actually diamond, because that can greatly affect the value of your jewelry. Here are a few simple tests to determine whether you have a real diamond or not.

Check the Setting

First of all, take a look at the setting of the stone. This won’t tell you for certain, but will give you a good idea. A real diamond will almost never be set in cheap metal. If your jewelry is made of real gold or platinum, however, then the stone is more likely to be diamond. Also check and see if there are any stamps—if the setting is marked with C.Z, your stone is a cubic zirconium.

Scratch It

You can try also scratching the stone with a piece of glass. Real diamonds are very hard and cannot be marked this way. However, some false stones can also pass this test, and even if the diamond is fake you might not want to scratch a piece that has sentimental value to you.

Use Text

Another technique is to place the gem on a page of text such as a newspaper. Real diamonds refract so much light that it should be impossible to see any of the letters clearly. However, depending on how they are cut, some imitation stones can also obscure the letters.

Fog It Up

True diamonds are very good at conducting heat, which means that you can breathe on them like you would a mirror. A real diamond will clear away fog quickly. On the other hand, so does mossanite, a high-end diamond substitute.

Get Professional Help

None of these tests are foolproof, but they can help you rule out most cheap diamond imitations. You may want to try using multiple tests to reach a firm conclusion. To know for certain, however, get your diamond appraised by professionals—AAA Jewelry would be happy to help.