Understand the authenticity certificate of diamonds

The authenticity certificate of diamond is an official document issued by an independent laboratory that guarantees the quality of the diamond you plan to buy.

The certificate is issued by an independent body of your diamond dealer. It guarantees the characteristics of the diamond that is presented to you, which characteristics justify the price of the diamond.

authenticity certificate diamondCertificate of a diamond G VS2 mounted on an alliance for a customer.


Free Bonus : Download our complete guide on Diamond (fr).

You'll discover all you need to know to buy diamonds jewelry online or in store.

Examples of diamond rings from our collection or made to measure :

engagement ring diamond engagement ring diamond engagement ring diamond


  1. The different types of diamond certificate
  2. How to read a diamond certificate 
  3. The main laboratories certifying diamonds
  4. Fake GIA certificates

Different types of certificate 

Each laboratory certifying diamonds has its own certificate design, but the information presented is very similar from one lab to another.

It includes a report number and diamond grading according to the 4C diamond rating (for more information on diamond 4C).

This report is tamper-proof since it can be consulted online on the site of the transmitting laboratory in order to verify that the inscriptions of the paper certificate correspond to the original report archived by the laboratory.

In the case of the certificate issued by the GIA presented here, the report data can be verified on the GIA website with the report number : 5186977170 available online here.

How to read the diamond certificate ?

All certificates consist of different blocks of information. It contains the report number issued by the laboratory, the main block of information relating to diamond grading and additional information on the diamond and its optical properties and finally the international scales of assessment of diamond quality.

comparative diamond

The most important for a buyer is the diamond quality information block, because these are the properties that make the price of diamond.

This GIA video will help you read your quality certificate :


The main certification laboratories for diamonds

Although the GIA is a well-known laboratory for diamond grading, there are many others that do the same job and are reliable :

    How to certify or authenticate a diamond ?

    You can therefore ask for your diamond to be certified or have it certified by contacting one of these laboratories mentioned above.

    In most cases, 0.3-carat diamonds sold in jewelery or online already have their guarantee certificate. But this is not an obligation.

    For low-weight diamonds that are not of exceptional quality, they are not generally certified since the cost of the certificate can equal or surpass the diamond price. It's therefore necessary that the quality (and therefore the price) of the diamond justifies such a certificate.

    Note that there are different types of certificates more or less complete and that prices vary.

    Ask the lab you contact, the prices of the different certification services they offer.

    To have your diamond certified, you must provide it not set on a jewel. A diamond set can not be graded and therefore can't be certified.

    Fake GIA diamond certificates

    The diamond offers two major handicaps for the buyer to appreciate the quality of what he has or what he will buy :

    • on the one hand you have to be an expert to judge the diamond quality
    • on the other hand the diamond quality can only be appreciated if not set on a jewel

    Therefore, when buying a jewel with diamond, the certificate is the key to guarantee the quality and value of the diamond set on the ring or jewel.

    Fraud on the sale of a diamond will therefore involve the provision of a fake GIA certificate (or of another laboratory) for a diamond of a lower quality than that described on the certificate.

    The case of this fraud GIA diamond certificate described by the company GGTL laboratories is an exemplary school case that you must read to understand the intricacies of this type of fraud.

    How to recognize a fake GIA certificate ?

    Various checks allow to suspect an attempt of fraud.

    Laser engraving

    • Large quality diamonds are always laser engraved, the first thing to do is to check that the laser engraving on the rounder corresponds to the report number of the certificate.
    • This is a necessary condition not sufficient.

    The impurities of the diamond

    • Most of the time, the certificate shows the shape and disposition of the inclusions in the diamond, thus representing its fingerprint.
    • Comparing the visible impurities of the diamond with those shown on the certificate makes it possible to check the consistency of the diamond with the certificate presented.

    The certificate itself

    The certificates of your diamonds present details that are little or not visible to the eye and difficult to reproduce by counterfeiters, just like banknotes:

    • holograms
    • special ink prints
    • inviolable fund printing
    • others not specified by the laboratories

    Comparing your diamond certificate with another certificate of which you are certain of the authenticity will allow you to remove any doubt as to the validity of the certificate of your diamond.

    In case of doubt, contact either a laboratory or a house recconu for advice.

    Free Bonus : Download our complete guide on Diamond (fr).

    You'll discover all you need to know to buy diamonds jewelry online or in store.

    For More Information :

    August 06, 2019 — TRANCHANT NICOLAS

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