Diamond Info & Grading

The more you know about diamond grading, the more you’ll appreciate your diamond purchased from the Jewelry Exchange. To help you make an informed decision, we have listed below some important information that you should know before purchasing your next diamond.

Important Information About Diamond Grading

The Jewelry Exchange sends diamonds to three different gemological research laboratories for grading: GIA, EGL USA, and AGS. Each lab has its own grading standards, so when comparing diamonds, we recommended that you compare diamonds with like certificates.

Gemological Institute of America

The GIA, the Gemological Institute of America, is the world’s largest nonprofit institute of gemological research and learning. Established in 1931, the GIA originated the famous 4C’s of diamond value and is the birthplace of the Diamond Grading System. The GIA color grades of D though Z and clarity grades of IF through I3 are recognized world wide by professional jewelers, diamond dealers and consumers as leaders in the industry. Diamonds with GIA certificates set the standards for diamond pricing.

European Gemological Laboratory – USA

EGL USA, the European Gemological Laboratory – USA, is one of the largest gemological institutions focusing on gemstone certifications and research for the jewelry trade. Originally part of an international network founded in Europe, EGL USA went independent in 1986 and is no longer affiliated with any other EGL labs outside of the US and Canada. EGL USA has incorporated a new clarity grade of SI3 as a way of identifying the exceptional I1 diamonds. Diamonds with EGL USA certificates can reflect a 6% lower price from GIA pricing due to borderline cases that receive a higher grade and the use of the SI3 grade which enables diamond pricing to be reconciled with the Rapaport pricing system.


The EGL USA Diamond Report is a comprehensive overview of the world’s most timeless stone. Identification and evaluation elements include the classic criteria of carat weight, clarity grade, color grade, cut (shape and style), finish, fluorescence, plotting, and proportions. https://www.eglusa.com/diamond-report/


The Colored Diamond Report captures the unique characteristics of diamonds distinguished by hue, tone, and saturation. This report contains all of the classic diamond report measurements. Plus, it includes color-specific criteria such as absorption spectra, color distribution, color grade, and color origin. https://www.eglusa.com/colored-diamond-report/


The Enhanced Diamond Report documents stones that have heightened visual appeal due to a special clarity-enhancing treatment. Clarity can appear to be improved due to the introduction of a glass-like material in natural feathers or fractures, a process known as feather or fracture filling. EGL USA provides a comprehensive evaluation of clarity enhanced diamonds, and clearly identifies them with laser inscriptions and unique reports. https://www.eglusa.com/enhanced-diamond-report/


The Lab-Grown Diamond Reportidentifies and evaluates man-made diamonds, also known as lab-grown or synthetic stones. These diamonds have essentially the same chemical, physical, and optical properties as natural diamonds. But, they are created through high pressure and high temperature (HPHT) or chemical vapor deposition (CVD). EGL USA provides a complete evaluation of such diamonds, and clearly identifies them with laser inscriptions and unique reports. https://www.eglusa.com/lab-grown-diamond-report/

European Gemological Laboratory – International

EGL International is made up of different independent labs located in the largest diamond centers in the world. There are 10 labs total, located in Antwerp, Johannesburg, Paris, London, Tel Aviv, Seoul, Istanbul, Mumbai, Delhi, and Cape Town. While EGL International shares the ‘EGL’ distinction with EGL USA, they remain completely different companies and it is important to understand some critical differences between EGL USA and EGL International.

Diamond grading is a very subjective skill that is performed by diamond experts that have years of experience in the industry. They thoroughly examine a diamond’s physical characteristics and render an expert opinion. Different experts have varying opinions on a grade. EGL International diamond grading standards have been noted as being consistently more relaxed than their EGL USA counterparts. This means that a diamond graded by EGL International could be as much as two color grades and two clarity grades higher than the same diamond as graded by EGL USA.

American Gem Society

AGS, the American Gem Society, is the world’s premier grading laboratory of diamond cut, and offers a cut grade for all fancy shapes and sizes. Established in 1996, AGS has gained the reputation as an industry leader in grading diamond cut. Until 2007, when GIA started grading the cut, AGS was considered the only recognized lab to use for diamonds cut to “Ideal” proportions. Diamonds with AGS certificates can command a 2% premium above GIA pricing because of their tougher standards and superior cut grading system.

The public should be aware that diamond grading is subjective; grades assigned are based on how each individual grader perceives the guidelines. Differences of opinions are discussed within the lab before a final grade is assigned.