Last updated on December 26, 2022
Have you ever wondered what the big deal is if you buy non-certified diamonds? Diamonds are an expensive purchase, and whether you buy a certified or non-certified stone makes a big difference. Let’s see what distinguishes a certified diamond from a non-certified one and why shopping for certified diamonds is a benefit in itself.
What Are Certified Diamonds?
Certified – understanding this term unlocks the entire question. The term “certified” means officially recognized as possessing certain qualifications or meeting certain standards. In the case of diamonds, certified means that the quality characteristics of a particular polished diamond are verified to meet certain standards by an independent third-party gemological authority.
Certified diamonds come with a certificate or a grading report, an official document issued by a grading laboratory describing a stone’s colour, clarity, cut quality, carat weight, shape, measurements, polish, symmetry, fluorescence, and other features of the stone.
When you buy a certified diamond, you are also buying the certificate, which should accompany the stone for life. Without this document, any claims about the diamond’s quality characteristics remain unverified, meaning you make a purchase based on the seller’s opinion.
Who Certifies Diamonds?

Diamonds are certified by independent third-party gemological authorities such as the Gemological Institute of America (GIA), International Gemological Institute (IGI), American Gem Society (AGS), European Gemological Laboratory (EGL), Hoge Raad Voor Diamant (HRD) and others.
Remember that certification makes sense only if it is done by a third party not connected with the jeweller selling the specific diamond. In case the jeweller can influence how their diamonds are evaluated, the quality characteristics may not be objective.
It is important to mention that appraisals are not certificates. A diamond grading report describes and grades the diamond, while an appraisal values the diamond according to current market prices. Moreover, a diamond certificate is not a certificate when it is issued by the jeweller or seller themselves.
Why Some Diamonds Do Not Have a Certificate?
Diamonds may come without a certificate for a variety of reasons. Certification costs money, and it does not always make sense on small or low-quality/inexpensive diamonds. In such a case, the benefit of a lab report is in question, but it adds significantly to the cost. However, it may be still offered if the buyer covers the cost of the certification.
Some grading laboratories refuse to certify enhanced diamonds. Others provide grading but note the type of enhancement. For example, GIA (Gemological Institute of America) does not issue grading reports for stones that have undergone non-permanent or unstable treatment processes such as fracture filling. They will issue reports for laser-drilled diamonds because this process is permanent but will disclose the presence of the treatment on the certificate.
And last but not least, some sellers prefer to offer non-certified or self-certified diamonds so that they can present the quality of these stones in the best possible light.
What If a Diamond Is Not Certified?

Certification is vital since it provides independent verification of a diamond’s quality characteristics. When evaluating stones, diamond grading laboratories follow strict guidelines. Labs try to make the process as accurate as possible by assessing each stone by multiple graders. However, the exact grade on any given characteristic comes down to the expert making the grading.
In fact, without a certificate, you can never be sure what you are buying. If a diamond is not certified, your only source of information about the stone’s quality is the seller. And let’s agree the seller’s assessment is not likely to be the most objective.
Due to the seller’s subjectivity of diamond grading, they can have some leeway when representing a diamond’s quality to the buyer. They can increase the colour and clarity of a stone, usually by no more than one grade up from what the diamond would be graded by an independent party. That is why if you want to make sure that the quality of the diamond is what the jeweller claims to be, always ask for a certificate and never buy non-certified diamonds.
Featured image: Wgi Labs, CC BY-SA 4.0 / Wikimedia Commons