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Diamond Certification
The most important certification document you should ask for when purchasing a diamond is a diamond grading report. The established international organisations that examine and appraise diamonds to produce such reports are the Gemological Institute of America (GIA), the European Gemological Laboratories (EGL USA and E.G.L. International), the International Gemological Institute (IGI), and the American Gem Society (AGS). Also commonly called diamond certificates, these comprehensive reports outline and evaluate a diamond's characteristics in its loose state (as opposed to within a jewellery setting). These include the 'four Cs' – carat size, cut, clarity and colour, as well as its measurements and additional aspects that contribute to its unique fingerprint, or 'diamond DNA'. A diamond sold without an official diamond grading report from the GIA, EGL USA, E.G.L. International, IGI, or AGS has not been formally verified, and should not be trusted or purchased.

Official Diamond Grading Report

  • The Gemological Institute
    of America (GIA)
    The most well-known international organisation offering diamond and gemstone grading, research, consumer advice, and training is the US-based GIA. As the global benchmark for high-quality diamond grading, this institute actually introduced the practice to the world in the 1950s. The GIA analyses and evaluates single, loose diamonds weighing 0.15 carats or more, listing their characteristics on an official document known as a GIA Diamond Grading Report. This document not only determines a diamond's overall value, but also records its unique 'fingerprint' in the event the diamond is lost, stolen or resold. Diamonds weighing between 0.15 and 1.99 carats may also be given a GIA Diamond Dossier, which outlines and grades the same characteristics listed in a GIA Diamond Grading Report, but without a plotted representation of the diamond's clarity characteristics. This certification also typically includes a laser inscription of the serial number.
    The international research group the European Gemologial Laboratories was founded in 1974 before splitting into two entities – EGL USA and E.G.L. International. Now completely independent and not affiliated with any other EGL organisations, EGL USA has been offering diamond and other gemstone certificates and grading since 1986, with offices in various parts of North America.
  • E.G.L. International
    E.G.L. International is also formerly part of European Gemological Laboratories, with a widespread presence in multiple cities across the world. Similar to other laboratories, E.G.L. International follows the industry's recognised standards in diamond certification, as well as offering gemmological training.
  • The International
    Gemological Institute (IGI)
    The world's largest independent organisation that evaluates diamonds and other gemstones is the IGI. It is also the only international certification laboratory that's owned and managed by a central governing body, which means that all its grading is controlled and consistent. They issue over one million reports globally every year, which include just not just diamond grading and other gemstone reports, identification reports, but authentication and attestation of origin. The IGI also provides gemmological training courses and laser inscription services.
  • American Gem Society Laboratories (AGS)
    The AGS also evaluates diamonds, grading their carat weight, cut, clarity and colour to standards as equally high and respected internationally as the GIA. Also based in the United States, the AGS gemmological research organisation appraises diamonds weighing 0.18 carats and above. They issue a number of reports, including an AGS Diamond Quality Document and an AGS Diamond Quality Certificate, utilising a grading system that ranges from 0 to 10. An AGS grading of 0 is the most optimum and desired grade, and diamonds with an AGS cut grading of 0 are recognised to have an AGS Ideal Cut - a highly exclusive distinction in the diamond industry.
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