To ensure the quality of your diamond it is highly recommended that you purchase a certified diamond. Certified diamonds are diamonds that have been graded by a gem laboratory based on the “4 C” attributes (Cut, Colour, Clarity and Carat Weight) of the stone.
Globally, there are several bodies known to specialise in diamond certification. These include:
- Gemmological Institute of America (GIA)
- American Gemmological Society (AGS)
- European Gemmological Laboratory (EGL)
- Diamond High Council (HRD, which is an abbreviation of the Dutch “Hoge Raad voor Diamant”)
- International Gemmological Institute (IGI)
- International Confederation of Jewellery, Silverware, Diamonds, Pearls, and Stones (CIBJO)
Despite, these names it doesn’t clear up what diamond certification refers to and the difference between these certification bodies.
To be clear, there is not a global standard regulating diamond certification. Each certification body formulates their own standard for diamond grades and valuations. The only global requirement is consistency across grading standards. Therefore, it would be likely that a diamond graded by AGS would be distinctly different to a grading produced by the IGI.
It is important to remember that due to the lack of global standards for diamond grading, each grading body is distinct from one another and therefore, not all as reputable as eachother. John Baseman an insurance underwriter for “Insured Diamonds” a leading diamond insurance company for wholesale diamond brokers stated:
“The most reliable diamond certificates (also called diamond reports) come from the Gemmological Institute of America (GIA) and the American Gem Society (AGS). These are the most respected labs, known for their accuracy and professionalism. These reports are not appraisals and do not carry valuations. Certificates from any other sources are often questionable and should not be relied upon by insurers.”
Mr Baseman made these comments because GIA has a reputation for rating colour and clarity, with the most stringent scales, more rigorously. The AGS is also well regarded for its grading standards and are preferred by some jewellers over GIA certification standards.
The other listed bodies are not as widely available as the GIA or AGS. The EGL are unique to Europe and have an entirely different grading system. CIBJO on the other hand are not commonly used and are not as transparent in their grading standards as GIA.
While the diamonds certified by lesser known bodies may be of good value we do note there is a risk. Commonly IGI graded diamonds are one or two colours removed from GIA standard. Despite your certificate saying E you may very well have a stone more closely coloured to a G by GIA standards.
And lastly, even though it is possible to purchase a jeweller certified diamond we do not recommend doing so. We at ADBW care about sourcing the most perfectly formed diamond with regard to the “4c’s”, therefore, we stock a large range of GIA and AGS certified diamonds.