Diamond Certification – The Diamond Grading Laboratories

It was not always necessary to have a laboratory report on a diamond being considered for purchase. In a time before the internet and before synthetic lab grown diamonds started to appear in the market, consumers simply found a trusted jeweler and picked out the prettiest diamond they could afford from whatever inventory he or she had to offer. This was how diamonds were traded for centuries. Actually, the first major laboratory was not even established until the 1930’s. The Gemological Institute of America (GIA) was founded in 1931 by Robert Shipley. A few years later their sister organization was formed – The American Gem Society (AGS). GIA issued its first diamond grading report in 1953. AGS would go on to start their own lab in 1996. Both labs are now considered the top echelon of diamond grading labs. While the GIA is much bigger with labs now located all over the world, AGS Laboratories (AGSL) is a small US based lab with a specialty in cut quality analysis. Both labs have a reputation for accurate and consistent diamond grading, and they are the two labs we recommend at Whiteflash.

Over the years other reputable labs have emerged and some have found large followings in different parts of the world, or in catering to particular constituencies. There are important differences between labs and their grading practices and reports. And there are implications for the value of a particular diamond depending on the lab report(s) associated with it.

With so much diamond trading occurring online today, both at the wholesale and retail level, a high quality laboratory report is now an expectation for any diamond purchase of significant cost. And understanding how to read a laboratory report is a big part of making a smart purchase. Before the advent of online diamond buying, a laboratory report was intended to be part of the in-person presentation of the diamond by a jeweler who could walk the customer through the metrics on a report while examining the diamond in person. Today, with many consumers buying online, it is important to have a solid understanding of the labs, their specialties, and especially their reputations.

This article will provide an overview of the most important diamond grading laboratories, though there are other labs also operating in the market.

The Gemological Institute of America (GIA) is the fountainhead of gemological knowledge in the diamond and gem world. In fact, most diamond laboratories in the world today have some indirect connection with GIA. Most employ staff that have at one time or another studied or worked at GIA. The foundational research done by GIA has influenced every lab to come after it. Though there are some minor differences in diamond grading between labs, the essential elements developed by GIA are followed closely by all major laboratories.

GIA is known and respected worldwide for its expertise and accurate and consistent grading. GIA accepts loose diamonds (Earth mined and lab grown), colored gemstones and pearls for identification and grading from both the trade and individuals. GIA has two laboratories in the United States –California and New York – and seven other labs spread around the globe.

GIA identifies synthetic diamonds as part of their diamond grading routine. A report issued on a lab synthetic is a different document and will clearly state that the diamond is lab grown, and the diamond will be inscribed as LG.

The GIA finally began issuing diamond grading reports with an overall cut grade in 2005. This had an immediate impact on cut quality among manufacturers who now had incentive to cut to the top GIA grade of Excellent, and GIA “triple Ex” quickly became a defacto standard in the market for a well cut diamond. However, there has been much debate in the trade about the broad and forgiving nature of the Excellent cut grade, which is not nearly as strict as the AGS Ideal cut grade. To date, GIA only provides a cut grade for round brilliants while AGS is capable of grading cut quality on a range of round and fancy shape diamonds using their state-of-the-art light performance cut grade system.

GIA will accept mounted diamonds and gemstones for identification, but to obtain a grading report the diamond or gemstone will have to be submitted unmounted. GIA does not do jewelry appraisals. That is, they will not render a dollar value on any diamond or gemstone. Their services are strictly analytical.

The American Gem Society (AGS) is a sister organization to the GIA, having been established in 1934 by the same folks that founded GIA. From inception the mission of the AGS has been to represent the best in retail jewelry practices, in particular in education and ethics. Their membership criteria require AGS stores to have a GIA Graduate Gemologist on staff, to have strong financial stability, and to have a great reputation in the trade. As a result of stringent requirements, only one in twenty jewelers in America have attained membership.

In 1996 The AGS established their own laboratory (AGSL), with a focus on cut quality analysis. They were filling a void left by GIA in terms of providing consumers with a full understanding of the most important of the diamond “4C’s” – Cut. As more consumers were learning about the impact of cut quality on diamond beauty and value, AGSL established itself as a world authority on the Ideal Cut, based in part on the work done by Marcel Tolkowsky in determining scientifically the proportions that result in diamonds with optimal brilliance and fire. With a deep commitment to the science, the researchers at AGSL continued their studies using modern technologies. This research culminated in an all new way of analyzing diamond cut quality in a scientifically rigorous and repeatable grading system utilizing sophisticated light ray tracing. The result was the AGSL light performance grading system released in 2005.

A diamond that receives a grade of Ideal on a light performance based AGS report has been scanned and ray traced with 30,000 virtual light rays, and measured for performance in the key attributes of brightness, contrast, fire and leakage and has been found to have zero significant deficits in any of those areas. The terms AGS 0 and Ideal are thus synonymous.

The real beauty of the approach that AGSL took to cut grading is that it is a system than can be potentially tailored to any diamond shape and facet configuration. In addition to round brilliant diamonds, AGSL now issues light performance reports on a range of fancy shapes including oval, emerald cut, and certain cushion cuts.

The AGS system is the only scientific and peer-reviewed cut grading system available in the market. An AGS “Triple Zero” report is considered the ultimate pedigree for cut quality among diamond laboratories. Diamonds with AGSL reports tend to command a premium over diamonds with any other certification, including GIA. *See chart at the bottom of this article.

Color, clarity and other vital data regarding the overall quality of the diamond is reported on an AGSL report in alignment with GIA standards, and many of the graders are students or graduates of GIA. Color grading master stones are all vetted by GIA to enhance consistency between the two labs.

The AGSL serves both AGS stores and the gem trade in general. Individuals looking to submit items to the AGSL can do so through AGS members.

AGS does not do appraisals. That is, they will not render a dollar value to any diamond or gemstone - their services are strictly analytical.

International Gemological Institute (IGI) is a large organization with 20 labs worldwide, mostly concentrated in India and located in cities with gem cutting centers. IGI serves the jewelry trade with many services. IGI issues grading reports on diamonds and gemstones, and even does jewelry appraisals. And they have taken a major role in screening synthetic diamonds for the trade.

IGI began providing full grading of lab grown diamonds in 2005, providing the beginning of standardization for this growing industry segment. Today IGI has extensive experience and expertise in lab-grown diamond grading.

In addition to issuing diamond reports with basic measurements and grades for color and clarity of both natural and synthetic diamonds, IGI also provides a hearts and arrows report that indicates important aspects about cut craftsmanship. While providing information pertaining to three dimensional facet precision, the report is not as comprehensive as a light performance based analysis such as AGSL provides.

IGI is one of the few labs to hold ISO accreditation. The Organization for International Standardization 17025 laboratory competence certification is considered the single most important standard for calibration and testing laboratories across the globe, covering all laboratory environments.

Education is a focus for IGI, offering a diversity of courses and an impressive reach. In-person and online courses are offered in multiple locations and online programs are offered as well. From rough diamonds to CAD jewelry design and retailing, IGI goes above and beyond traditional diamond and gemstone training, graduating thousands of new jewelry professionals each year.

IGI appraisals are possibly a reason for some loss of credibility and trust in the marketplace, as has been the case with other labs that issue appraisals. As a service to the retail trade, IGI will issue valuations on diamonds and jewelry. In many cases those valuations have turned out to be inflated, and have been used as selling tools by retailers. Misleading information about value has caused some in the marketplace to question the ethics of IGI and the retailers they service, undermining their reputation in the industry.

The Gem Certification and Assurance Laboratory (GCAL) was established in 2001 by Don Palmeiri. They provide a full range of gemological services and analysis, with operations in New York’s diamond district. In addition to identification and grading of both natural and lab grown diamonds, GCAL provides analysis on colored gemstones and pearls and also does appraisals.

Their diamond reports have evolved in complexity with the recent launch of their “8X” diamond report. The comprehensive analysis includes color, clarity and other key measurements as well as detailed cut quality aspects including a variety of light performance images, and includes a Gemprint laser fingerprint of the diamond which provides a further method of positively identifying the diamond.

GCAL is an ISO 9000 certified laboratory, demonstrating a commitment to quality and consistency. They also provide a unique grading guarantee, although it is uncertain how disagreements would actually be resolved. Some of the methodologies in the area of cut grading are opaque, with the oft-used characterization of “proprietary” making it difficult to independently verify validity.

GCAL does not accept submissions from individuals. Submissions must be accompanied by a letter specifying services requested on company letterhead.

The history of HRD Antwerp is intertwined with that of The Antwerp World Diamond Centre (AWDC). The latter is a private foundation, established in 1973 as the Hoge Raad voor Diamant (HRD) or Diamond High Council at the initiative of the Belgian government and diamond industry representatives.

In 2007, the Diamond High Council was restructured and split into two different enterprises: AWDC and HRD Antwerp. As the official representative of the diamond community, the AWDC is committed to boost business in the rough and polished diamond trade, as well as manufacturing, by organizing B2B initiatives. HRD Antwerp, on the other hand, became a leading authority in diamond certification.

Screening for synthetics is a major service provided to the trade by HRD, including screening large quantities of diamond melee very quickly with advanced detection devices.

They issue grading reports on both natural Earth-mined diamonds and lab grown synthetics. Lab grown reports have a distinctive report format and the diamond is inscribed “LAB GROWN” on the girdle. Documents range from a full report, to a scaled back credit card sized report that encases the diamond, to preliminary consult reports.

A Hearts and Arrows grading report can be obtained from HRD, providing additional information about cut craftsmanship and optical precision.

HRD also provides reports on finished jewelry. According to their website, this analysis “provides a general description of the jewel, the diamonds it contains and the precious metals of which it is made.” This document is helpful in obtaining personal jewelry insurance, however HRD does not provide valuations (appraisals).

In addition to identification and grading services, HRD also provides education and training offering courses in polished diamonds, rough diamonds, and gemology. In this and other respects HRD is similar to IGI.

Serving primarily the trade, HRD requires registration and the filing of company credentials in order to obtain their services. There is also a form for a private client to submit for service. HRD is a respected lab that is much better known in Europe than in other parts of the world.

The European Gemological Laboratories (EGL) is an interesting case. Perhaps no gemological organization has as mixed a reputation as EGL. This may derive from the business model of this collection of labs. They are not unified under a common management hierarchy. As a result, their grading practices vary among the labs, with some such as EGL USA maintaining a much better reputation for accuracy and consistency than some of the other labs in other locations. In fact, questionable grading in a couple of the labs has had a very detrimental impact on all the labs under the EGL banner.

One of the unique things about EGL is their introduction of the Si3 grade. This may be another factor contributing to their reputational challenges. It means that a much higher percentage of diamonds graded by EGL stay out of the Imperfect grade, which is a quality level that is a non-starter for most consumers shopping for a good quality diamond. While it is true that the Si2 grade is broad, segmenting it further results in Imperfect diamonds being presented as Si diamonds, which does not promote confidence in the market.

The chart below is a snapshot that paints a picture of the values the diamond trade places on reports from different labs. Listing prices for diamonds of similar size and grade were analyzed by the largest international database and broken out by the laboratory report that accompanied the offering. Notice that EGL USA rates much better than the other EGL labs surveyed. Also notice that diamonds with AGS reports trade at a premium over GIA, speaking to the high regard that AGS graded diamonds are accorded by the market.

Gemological Science International (GSI) is headquartered in New York, NY and purports to have 13 laboratories on four continents and in a number of countries: the United States, India, Dubai, Israel, Belgium, Hong Kong, and Botswana.

Established in 2005, GSI touts themselves as the only major gem laboratory founded in the 21st Century, and dedicated to using the most modern technologies ln their gemological services.

Screening and grading laboratory grown diamonds is a major focus for GSI, though they also grade natural Earth mined diamonds and colored gemstones as well. They cater mainly to the large chain retailers. However, searching for a retailer in Houston, Tx (which is the 4th largest market in the US) yields no results. This would indicate that GSI is not as popular in the US as it may be in other parts of the world.

In 2007 GSI teamed up with GemEx to incorporate light performance analysis to their reports. GemEx has a proprietary technology that purports to measure brilliance, fire and scintillation, though its technology was not widely adopted by the trade. At the time of this writing we are unsure if the association between GSI and GemEx is still in effect. Searching GSI report on the GemEx website yields no results.