Grading Laboratories & Certificates
Below, we are going to give you a brief overview of the different main grading laboratories from around the globe.
In short: Five labs grade diamonds for the UK trade — GIA (gold standard, strictest), IGI (preferred for lab-grown), HRD (Antwerp), AGS (0-10 scale, now part of GIA), and EGL (more lenient, less trusted). The same stone graded GIA versus IGI typically differs by 1 colour and 1 clarity grade. For Hatton Garden purchases, always insist on GIA or IGI certification with girdle laser inscription.
GIA - THE GEMOLOGICAL INSTITUTE OF AMERICA
There is only one place to begin, and this is with the Gemological Institute of America. The GIA was founded in 1931 and its headquarters are in New York. It developed the first ever Diamond Grading System that was accepted internationally. They aim to service consumers with objective and independent assessments regarding diamond quality, and their grading system is widely regarded as the strictest. The three GIA certificates are the GIA Diamond Grading Report, a colour report focusing on diamond identification and origin, and a dossier, which is for diamonds that weigh less than one carat.
GRADING LABORATORIES & CERTIFICATES
The EGL has labs all over the world, from London and Mumbai to Antwerp and Tel Aviv. The same standards apply to all laboratories, and the EGL has a different approach to grading when compared with the other leading laboratories. Certificates issued include the EGL Diamond Certificate Report, the CertiCard, which is a compact credit card like certificate, and the mini certificate, which falls between the two.
EGL USA - THE EUROPEAN GEMOLOGICAL LABORATORY UNITED STATES OF AMERICA
The reason why the US version of EGL gets its own mention is because it is not owned and overseen by the same entity as the EGL mentioned above. It is compromised of four North American based labs and it provides the following certificates - EGL USA Diamond Certificate, a report on Coloured Diamond Origin, and a Coloured Diamond Analysis Report.
IGI - THE INTERNATIONAL GEMOLOGICAL INSTITUTE
The IGI is a leading global gemological institution. It was founded in Antwerp in 1975 and has a sister lab in New York. They pride themselves on an objective view, and they are not associated with any commercial sales. With more than 250 experts, it’s remarkable to think IGI only began with three members. Certificates issued include the IGI Diamond Report, a report on the hearts and arrows diamond effect, and IGI Diamond ID. For more information on the hearts and arrows effect, take a look at our page.
HRD - THE DIAMOND HIGH COUNCIL – HOGE RAAD VOOR DIAMANTE
HRD is a non-profit organisation that was founded in 1976. It is now one of the biggest diamond certification labs on a global scale and has an outstanding reputation. Sophistication machinery is used to determine diamond quality. Certificates issued include the HRD Diamond Certificate, as well as a colour certificate and identification report.
AGS - THE AMERICAN GEM SOCIETY
Robert Shipley founded the AGS in 1934. It’s a trade association that is situated in Las Vegas and it consists of carefully chosen industry experts, suppliers, independent appraisers, and retail jewellers. They issue both a diamond quality document and report. The latter includes GIA terminology as well as AGS terminology and the former is more detailed, including illustrations and diagrams.
