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Diamond Certification

Most of us have heard of diamond certification….but what does it mean, and which authority should I trust?

While some shoppers ignore the need and many jewellers insist you do not need them, diamond certificates are extremely important and are generally a consumers’ only guarantee as to the quality (and value) of the diamond they are purchasing.

Whilst common sense would suggest that a diamonds grade would be consitent across the industry, unfortunately as grading can be subjective, many companies take advantage of their position and offer certificates that can grossly overstate the quality of the diamond, allowing the retailer to either appear to be good value....or simply make a quick buck.


The holy grail of diamond grading is the Gemmological Institute of America (GIA) Every diamond sent to them is done so anonymously,  and is independently graded by 3 separate diamond graders (arbitration being used if any of the grades conflict).

The GIA are a fully independant  and non profit organisation. They have nothing to gain by the over-grading of stones and hence have the strongest reputation in the diamond industry. 

That is not to say that the GIA are the only company to use, but they are the easiest to trust. Many other companies such as the HRD ( and IGI ( are commonly trusted by the trade. 

"...Consistently been grossly overstating the quality'

There are some however that should definitely be avoided. The main one, which you may have heard of in the press recently is EGL International. They have recently had their license revoked by the EGL franchise, and the listing of EGL diamonds have been restricted by most diamond trading platforms as they have consistently been grossly overstating the quality of the diamonds they grade.

In my experience the EDR should also be avoided. I recently sent an EDR graded 2.00ct D VS1 diamond to the GIA which came back as a 2ct G SI2 – that is a considerable 3 colour grades and 3 clarity grades out. In terms of value a 2ct D VS1 would be in the region of £40-45,000; and 2ct G SI2 would cost in the region of £17-20,000!

If you would like any advice on a particular grading authority, or for us to source you a specific diamond, please get in contact using, or by calling +44 (0) 207 242 5775.


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