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Diamond Certification

Not all Diamonds are sold with certificates. Certified Diamonds have to be submitted to a Diamond grading laboratory to be appraised under strict laboratory conditions. The cost depends on various factors such as the and is set by the organisation producing the report. 

Independent Diamond certificates (as opposed to in-house reports produced by retailers) provide greater reassurance for consumers. But some laboratories have been known for slightly more lenient grading. For this reason laboratories such as GIA (see below) are favoured over other laboratories such as EGL. 

Theoretically, you can obtain any size certified Diamonds but we generally provide certificates for most stones that are 0.30carats in weight and over. For smaller Diamonds, the cost of the certificate is a greater proportion of the stone price and can often be more costly than necessary. It is important to purchase your Diamond from a reputable source providing you with the peace of mind you deserve. The smaller Diamonds we sell, if not certificated, always meet the grades we describe them as. Full disclosure of weights, colours and clarities are always provided in the accompanying appraisal. If you require a certificate with a smaller Diamond, please feel free to let us know as this will not be a problem.

Gemological Institute of America (GIA)

The Gemological institute of America was established by Robert M Shipley in 1931. It has been dedicated to ensuring the public trust in gems and jewellery by upholding the highest standards of integrity, Academics, science and professionalism. Many of the worlds finest Diamonds have been graded by the GIA such as the Hope Diamond and the DeBeers Millennium Star. It is also the creator of the 4 C's of diamond value now adopted internationally. Most Diamonds below 1 carat with GIA certification include a laser inscription of the report number on the girdle of the stone. 

International Gemological Institute (IGI)

IGI is one of the world's largest independent institutes handling a large majority of the worlds certified Diamonds. It is renowned for its quality services, extensive experience and know how. It was founded in 1975 and along with its sister laboratories, is one of the leading gemological institutes worldwide. IGI issues more than reports on certified diamonds each year. 

European Gemological Laboratory (EGL)

Established in 1974 in Antwerp, EGL now has laboratories worldwide and is an internationally recognised gemological laboratory providing comprehensive Diamond grading reports for the certified diamonds. EGL Antwerp came under recent scrutiny after an industry-wide call for greater consistency and stricter grading. 

American Gemological Society (AGS)

The American Gem Society was founded in 1996. It has been dedicated to setting the highest possible standards of business ethics and professionalism in the jewellery industry. This laboratory is regarded as one of the most reputable in the entire world. Our only criticism of this great laboratory is that there are relatively few Diamonds in circulation that are certified by AGS, but their reputation is well known amongst seasoned jewellers. 

HRD (Hoge Raad voor Diamant)

Established in 1973 as the 'Hoge Raad voor Diamant' or 'Diamond High Council,' the organisation has become the major employer of the Antwerp Diamond sector. The HRD acts as spokesperson of the sector towards authorities and third parties and offers a wide range of services including the issue of certified Diamond reports for loose polished Diamonds from the HRD Certificates Department. It issues one of the world's most respected Diamond certificates and jewellery reports and is the first Diamond lab in the world that is NBN EN ISO/IEC 17025-certified.


IGR laboratory is a London based diamond grading laboratory. They provide a range of services and Diamond grading reports and their UK location provides a convenient location for UK jewellers ensuring a fast turnaround on Diamond certificates. The informative IGR website is nicely presented, with a great insight into the style of their reports and the range of services provided.  


AGI is an abbreviation for Antwerpse Gemologische Instelling. Their byline is 'understanding Diamonds.' They are located in Antwerp and Manchester, making UK Diamond certification convenient, with full-size Diamond grading reports available for Diamond submitted. Their service is speedy and reliable. They have been operating in the UK since 2000, and now have over 13,000 clients Worldwide. Like GIA, their website offers a validation service enabling owners to enter the report number for details of their Diamond.