The first noticeable fact about natural color diamonds certificates is that their color is different from the ones of colorless diamonds.
When reading a natural color diamond certificate one has to keep in mind the limits of the colored diamonds grading system. Indeed, certain criteria only exist because they are used for their colorless counterparts (this is the case for the Cut and the fluorescence). The most important pieces of information to look for are the stone’s weight, its natural origin and the possible treatments. These can be HPHT, laser drills, heating (for black diamonds), irradiation or coating (which isn’t done anymore). Considering treatments, you might find the term “undetermined”, which means the laboratory has not been able to prove the natural origin of the stone’s color. Then you can look at the name given to the color of the stone, knowing the limits of laboratories on the matter. Finally, you can check the Clarity of your stone, knowing that Clarity criteria vary according to the diamond’s color.
Of course, a certificate is an important document, but it only provides an approximate idea of a stone. When purchasing a natural color diamond, nothing can be better than seeing it in real or at least, seeing a picture of it. Indeed, every natural colored diamond is unique.
Color Only Certificates
All the main laboratories also deliver certificates that are only focused on the color grade and its origin (natural or treated).
They are called “color only reports” or “half certificates”. These only indicate the color, the carat, and the shape of the diamond.
This shows that the last two Cs (Clarity and Cut) are far less important to the natural colored diamonds than to the colorless ones. This fact is attested by the numerous stones with color only reports that are frequently encountered in Christie’s and Sotheby’s sales.
Treated and Synthetic Colored Diamonds Certificates
When a colored diamond has been treated, it is specified on its certificate. This is why it is so important to know how to read color diamond certificates.
At the beginning, laboratories didn’t issue any certificates for synthetic colored diamonds. Nevertheless, they have recently expanded their expertise to lab-grown stones weighing 0.15 carat and up.
These specific certificates differ from one laboratory to another: