Gemological certification is only of value if it is recognised by the diamond industry.
A gemological certificate gives the following detailed information:
- Carat, the weight of the diamond
- Colour, the colour grades of the diamond
- Clarity, the clarity of the diamond
- Cut, the cut of the diamond
- Degree of fluorescence of the diamond
- Quality of its cut (or its proportions), only with round brilliant
- Polish of the diamond
- Symmetry of the diamond
- Dimensions of the diamond: diameter, height or thickness, minimum and maximum diameter at the girdle in millimetres
- Thickness of the girdle, the cut of the tip (culet), the table percentage
- Date of issue of the certificate
- Every structural defect of the diamond has to be noted on the certificate
- Plotting of inclusions on the diagram (drawing), if present
The certificate is similar to an identity card for the diamond and will thus prevent it from ever being confused with another one.
It is a laminated printed document which lists the qualities of the examined diamond. Holograms, special textures and microtexts have been incorporated into the certificate in order to prevent imitations.
Gemology laboratories provide various kinds of certificates which are produced in different formats (large, small, credit card-sized etc.).
They also offer additional services, such as inscribing the certificate number on the diamond by laser or the option of having the diamond sealed in a plastic box.
Nearly all gemology laboratories websites have an online facility for checking both the existence of a gemological certificate and the consistency of the information. To do so, it is sufficient to specify the number of the certificate and the weight of the diamond in carats.
HRD: HRD Antwerp Certificate
GIA: GIA Check Report |
(valid for certificates issued after 1 January 2000)
IGI: IGI Online Data Retrieval
((valid for certificates issued after June 2004)