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Certification – The 5th C

Certification is proof of a diamond’s 4C’s grading.

Although many diamonds look the same, they are not all going to be of equal quality. Diamond certification is the written proof of a diamond’s attributes. Without it, you have no assurance the diamond you are buying is worth the price you are paying.

With diamond certification, you know the precise grading for each of the 4C’s – carat weight, cut, color and clarity – and, therefore, the diamond value.

Certification gives you the information you need to assess a diamond’s fair market value. It also allows you to make informed comparisons with other diamonds either in the same jewelry store or in another and find out how much you should spend on a diamond.

Diamond certificates are issued by independent gemological laboratories. There are several grading laboratories, the most prominent being:

  • Gemological Institute of America® (GIA)
  • American Gem Society®Laboratory (AGS)
  • International Gemological Institute (IGI)
  • Gemological Science International® (GSI)

When you buy a certified diamond from a trusted jeweler, ask to see the diamond certification reports that will accompany the diamond when you purchase it.


The Leo Diamond® comes with an additional certification from GemEx® Systems.

The most critical aspect of the inherent beauty of a diamond is its brilliance. Every Leo Diamond® comes with an additional certification from GemEx® Systems that verifies its “Return of Light” — the level of brilliance your diamond achieves. GemEx® is the leader in brilliance certification. The certification it provides is based on scientific measurements of white light, colored light and scintillation taken with a GemEx® BrillianceScope™.

The Leo Diamond® was the first diamond ever independently and individually certified to be visibly brighter. Your GemEx®certification is proof of your Leo Diamond’s superior brilliance.

Authorized Leo Diamond jewelers let you compare The Leo Diamond®‘s brilliance with other diamonds through a GemEx viewer or in-store interactive tablet.

LeoDiamond GemEx Certificate