Buying a Certified Diamond


One of the most important factors when learning how to buy a diamond is certification. A diamond that is certified tells you that a gemological laboratory has evaluated it.

The process itself is actually quite scientific, done in laboratories by individuals whose careers are built on studying gemstones. They evaluate a diamond’s quality and unique characteristics, giving you the proof that the diamond you want to purchase meets the claims of its seller.

The key is knowing what certification is reliable. Even if a jeweler offers an in-house certificate, it is vital to ask for a third party diamond certificate form one of the five most trusted gemological laboratories. Many big box stores, and even major design houses, only offer in-house appraisals and certification.

Always Buy Third Party Certified Diamonds

Trusted laboratories for diamond certificates:

  • Gemological Institute of America (GIA)
  • American Gem Society (AGS)
  • EGL USA Gemological Laboratory (EGL)
  • International Gemological Institute (IGI)
  • HRD Antwerp (HRD)

Diamond certificates from these sources feature multiple security features to protect against altering and falsification. If ends are peeled, or if it looks as if the certificate or grading report has been modified, it is best to deal with a different jeweler. You can also go online to verify that the report in your hands matches the information stored in the applicable laboratory’s database.


Grading reports and certificates are called:

  • AGSL Diamond Quality Document
  • GIA Diamond Grading Report
  • GIA Diamond Dossier
  • GCAL Certificate of Diamond Authenticity

“The GIA Diamond Grading Report includes an assessment of the 4Cs – Color, Clarity, Cut, and Carat Weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions,” explains the GIA.

GIA report example

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