Nowadays certificates are standard in the diamond and jewelry industry.
Most diamonds come with a third party certificate from one of the three
major international gemological institutes: Gemological Institute of
America (GIA), International Gemological Institute (IGI) and Hoge Raad
voor Diamante (HRD, High Diamond Council). They use the same
nomenclature, hold up the same high standards and represent the overall
trend of standardized diamond graduation. In fact, only by using the
same high standards that make third party certification reliable and
comparable diamond sales over the internet became possible. Even more
than that: Third party certification is preferred by most customers to
any in-house certificate of a jeweler which makes buying diamonds online
the better choice. Many even take it one step further and consider
diamonds a commodity since certification makes it easy to compare gem
GEMOLOGICAL INSTITUTE OF AMERICA (GIA)
The Gemological Institute of America (GIA) was founded already in 1931 and has become the industry´s standard for graduation and appraisals over the years. GIA is known word wide not only for their research and certification, but also for their contribution to standardizing gem stone grading. The famous “Four C” are the basis of the common diamond language was introduced by GIA. Especially for grading diamonds GIA set new standards by updating their grading norms in 2005. Besides its professional expertise GIA´s status as a non-profit organization gives it an extra bonus of integrity. The only two downsides these days: Due to high demand and long waiting periods diamond grading takes around 5 weeks. Also, they have no European office or laboratory which means one has to send the diamond away to the U.S. resulting in additional costs and delay.
INTERNATIONAL GEMOLOGICAL INSTITUTE (IGI)
The International Gemological Institute (IGI) was founded in 1975 in Antwerp, Belgium, and is one of the leading international gemological institutes. IGI is the biggest centrally managed laboratory with over 450 workers worldwide- every year they certify over a million diamonds. In diamond grading IGI follows the American standards by GIA in color and clarity, their evaluation of the cut is based on the IDC-rules (International Diamond Council). Many see IGI as GIA´s European counterpart.
HOGE RAAD VOOR DIAMANT (High Diamond Council, HRD)
The Diamond High Council (HRD) was founded in 1976 in Antwerp, Belgium, and is an internationally well-respected gemological institute. The ISO accreditation (EN ISO/IEC 17025) guarantees high quality standards of grading and working processes that are certified externally by a third party. Diamond grading follows IDC rules but were slightly adjusted to American dominated markets in 2014. Even though HRD is a commercial institution, its owner AWDC (Antwerp World Diamond Center) is a quasi-governmental organization that promotes the diamond industry in Antwerp. HRD is very popular in Europe and Asia (especially Dubai) and is considered a solid alternative to GIA.
DIAMANTPRÜFLABOR (DPL, Diamond testing laboratory)
The Diamant Prüflabor GmbH (DPL) in Idar-Oberstein, Germany, was founded in 1977 and works according to IDC rules. DPL is the leading German institution when it comes to diamond grading and is the only laboratory certified by ISO Standard (DIN EN ISO/IEC 17025:2005). The laboratory is located in the same building as the German Gemmological Association, a non-profit organization in Idar-Oberstein and is well-connected as a member of the International Diamond Council (IDC). DPL is a commercial institution, however, it does not appraise diamonds nor does it take part in the diamond trade. Another plus for their integrity is the anonymous grading process by several diamond graders in the laboratory. And: DPL is liable for the correctness of their certificates.
EGL International and EGL USA
Founded in 1974 in Belgium the „European Gemological Laboratory“ is an internationally known, yet sometimes controversial market actor in the diamond industry. EGL USA is an independent gemological institute since 1986, however, both institutes share the same standards. Neither EGL International, nor EGL USA are non-profit organizations. One unique feature to EGL certificates is the clarity grade “SI3” that is established to some degree in the trade but not recognized by most gemological institutes. This clarity grade refers to “eye-clean” stones in between SI2 and I1. Diamonds by EGL are usually sold with a discount since their color and clarity appraisal tends to evaluate always be one or two grades above other international institutes. There are controversial because they use the same nomenclature as GIA or IGI which many consider misleading. On the other hand they have been in the market for many years already.
In diamond certification small details in proportions and angles and the evaluation of the same make the difference. However, also cultural aspects matter: In Europe for instance people tend to prefer round brilliant cuts with larger tables to maximize brilliance. In the United States a brilliant smaller tables to maximize fire is considered most desirable. Within the range of the excellent cut grades there is no better or worse per definition, but rather a difference in taste or in the individual ideal of beauty.
Institutions like such as the International Diamond Council (IDC) that was founded in 1975 by the world association of diamond exchanges and diamond polishers helped in standardizing diamond grading. Today most researched gem stone is in fact diamond. Constantly improving technical possibilities like automated polishing machines, devices for color detection and optical laser equipment to determine the exact proportions and measurements of a diamond eradicate human error step by step. This makes diamond grading more objective. Nevertheless, in diamond grading the benchmark for appraisal is still the “character” or appearance of the gem stone in total. Especially in clarity grading the features of the stone are not quantified but qualified which means that not the mere number of inclusions counts but their influence on the overall look of the diamond. In other words: Clarity grading is based on subjective expertise at a diamond grader´s own discretion. However, this tolerance at discretion is bound by such tight limits that the results are repeatable by trained diamond graders.