6 simple ways to spot a fake diamond

If you would like to buy a diamond or ensure that the one you have received is a real stone, there are simple ways to distinguish a fake diamond from a natural one even if you are not an expert.

Without getting too technical, we are happy to share some tips that can help you tell 'fake diamonds' from natural ones when purchasing the precious gem:

  • If the stone is mounted, check the metal and the stamps. A diamond is unlikely to be set in a cheap metal mounting (silver, gold-plated,..)
  • Use a jeweler loupe to give it a close look, fakes usually look too perfect and rarely show inclusions (imperfections) the diamond may have. However, this is not a determining factor as diamonds can be flawless.
  • Check how your stone behaves with light. A natural diamond has a high refractive index and shows great brightness whereas simulants such as moissanite or CZ have a greater prismatic effect, meaning they have a stronger 'fire' that could be described as the rainbow colors
  • Remember that a diamond is always singly refractive, if your stone is unmounted, place it on a sheet of paper with text printed on it. If you can read the text or if you can see clear indications of lines, dots or even full letters, you have probably got a fake. A diamond refracts light (=bends it sharply) so strongly, characteristic to which it owes its outstanding brilliance, that you would not be able to see the print.
  • Again if your stone is unmounted, drop it in a glass of water. A real diamond has a very high density so it will sink while most of its substitutes will float at the top or in the middle of the glass.
  • Diamonds are some of the hardest materials on earth. A mineral's hardness is determined by its ability to scratch or be scratched by other materials. Examine your stone closely, if it appears to be somewhat scratched around the facets, it is probably not a diamond but one of its softer substitute such as colorless topaz. 

Moreover, there are two important facts to know while buying diamonds:

  • there exist diamond simulants: this material only try to imitate the appearance of diamonds (sometimes very successfully so) but do not share the diamond's physical or optical properties. A simulant can be of synthetic origin, these include CZ (cubic-zirconia), moissanite, synthetic rutile, glass...Natural colorless sapphire, spinel, topaz or quartz may also be used to imitate diamonds.
  • on the other hand there exist diamond synthesis: these possess the same gemological properties as the natural diamonds except that they are man-made in a lab as opposed to natural diamonds that have grown in nature.

For maximum reliability, we recommend to have your stone checked by a professional appraiser.

As certified gemologists, we will be happy to assist you in finding out proof that your stone is real! In this case, we will also provide you with a certificate of appraisal. Feel free to contact us for advice or appraisal at info@geminfinity.com or +41 21 311 44 80. 

Fanny Ducommun