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Know how to read a certificate

Before offering your jewel or diamond for sale, it is important that you understand the quality of your stones as well as the details that give it its value. That way you know if you're getting a fair price and can make sure you're getting an honest deal. 

There are several factors that determine the value of a diamond or gemstone. One of the easiest ways is to understand your certificate and how your stone was certified. 

There are several reputable laboratories  and one of them is the Gemological Institute of America (GIA), which is the world number 1 for the certification of diamonds. There are also other certificates such as Gübelin or SSEF which specialize in the certification of colored stones other than diamonds. 

We'll help you decode a GIA certificate so you can ensure you're getting the best possible value for your diamond!

Here are the important points that make up your certificate:

  1. Laser inscription
    Often GIA certified diamonds have their certificate number laser engraved on the girdle of the stone. This number must correspond with the certificate number you have in hand. If the number is not the same, it means that you do not have the correct certificate. 


  2. shape of the stone
    The certificate informs you of the shape of your diamond. There are many different shapes for a diamond such as: round, pear, cushion, princess, radiant, and many more. 
    The shape of the stone refers to the arrangement of the facets on the diamond. Facets are the flat surfaces that you can see on your diamond when looking at it closely. 


  3. Diamond measurements
    The certificate always informs you of the measurement of your diamond. For round diamonds, measurements are presented in the following format: minimum width - maximum width x depth. 
    Diamonds other than round are measured by their length x width x depth. 
    These measurements are calculated to the hundredth of a millimeter, so they are extremely precise. You can know the exact size and dimensions of your diamond by comparing your measurements on your stone with those indicated on your certificate. 


  4. carat weight
    The weight of your diamond is always indicated in carat. To calculate its carat, the diamond was weighed to the thousandth of a carat with a very precise digital measuring device. It is always indicated to the hundredth on the certificate. 
    For example, a two-carat diamond weighs about the weight of a small paper clip. 


  5. Color
    The color of a diamond determines the amount of yellow present in the stone. The  ideal color of a diamond is "colorless", which means that the stone has no yellow tint at all. 
    There is a scale for classifying the color of diamonds relative to each other. Color test stones ranging from D to Z can be used to compare the color of a diamond with the color of another diamond in order to determine its color._cc781905-5cde -3194-bb3b-136bad5cf58d_
    The color scale runs from D to Z, with D being the whitest color for a diamond. 


  6. Purity
    The level of clarity of a diamond depends on the number of its inclusions, the nature of its inclusions, the size of its inclusions as well as the position of the inclusions in the stone. 
    Some inclusions can be seen with the naked eye, but often it is necessary to use a 10x magnifying glass to properly determine the inclusions and imperfections in the stone. 
    The purity is determined according to a scale ranging from "IF (Internally Flawless)" to "I3" (pitted)". IF means that there are no visible inclusions in the stone after having examined it with the magnifying glass, c is the highest purity there is for a diamond. "I3" means that the inclusions are visible to the naked eye. 


  7. Size
    The cut of the diamond represents how the facets have been cut and how they work to reflect light. It is the factor of the diamond which has the most importance on the brilliance, the luminosity and the beauty of a diamond.  
    a perfectly cut diamond has a distinctive and enormous return of light, called fire. In contrast, a diamond with a medium or low cut does not reflect much light and will be considered flat and lifeless. 
    Cut is an important factor in the value of your diamond.


  8. Polishing
    The polish of a diamond refers to its finish and how levelly, or evenly, the facets have been placed on the surface. 


  9. Fluorescence
    Your diamond's fluorescence is its reaction to long-wave ultraviolet radiation. The fluorescence of a diamond varies from zero to very strong. A diamond without fluorescence is more valuable than a diamond with. 


    The comments section on all diamond certificates is a place used to note any characteristics of the diamond that are not discussed elsewhere. It is also a way to mention elements that are not represented on the diagrams. 

Our experts are at your disposal for a free expertise!

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