AGS Diamond Certification

Founded in 1943, the American Gem Society (AGS) is dedicated to upholding the highest standards of ethics and integrity in the diamond and jewelry industries. Among the main priorities of the association is top-notch industry education, with numerous courses offered to jewelry professionals and consumers.

Brief History of AGS

In 1996, the AGS established a laboratory to provide modern gemstone grading services for the diamond marketplace. Its conservative, thorough approach to diamond grading has made the AGS one of the world's most respected gemological laboratories.

Learn more about the diamond reports issued by the AGS below.

Brief History of AGS

AGS Diamond Grading Standards

Every diamond graded by the AGS is analyzed for its color, clarity, and cut by at least two gemologists. Carat weight and proportions are measured using carefully calibrated computerized instruments. The AGS uses a unique numerical grading system to quantify diamond color, clarity, and cut. A grade of 0 indicates the rarest, most valuable quality, while a rating of 10 is the least desirable. Each number corresponds to a grade on the GIA's internationally accepted diamond grading scale.

Diamond Carat
Carat weight is measured to the third decimal place using a digital carat scale. The physical size of a diamond is electronically calculated in millimeters.
Diamond Color
A diamond's color is graded by comparing it to master stones of predetermined color.
Diamond Clarity
Clarity is determined by examining the diamond with a binocular microscope under specialized lighting; characteristics are plotted on a diamond diagram.
Diamond Cut Grade
Cut Grade is assessed with the AGS Performance-Based Cut Grading System. The computerized device uses revolutionary hardware and software to create a three-dimensional model of the diamond, and then rates values for light performance including brightness, dispersion (fire), leakage, and contrast. The diamond grader analyzes the proportions including girdle, culet, weight ratio, durability, and tilt. A diamond's finish is determined based on polish and symmetry. A diamond with optimum light performance, proportions, and finish will attain the coveted 'triple zero' status, a testimony to the exquisite craftsmanship of the diamond's cut.

AGS Diamond Quality Document

The Diamond Quality Document provides a complete assessment of the stone's color, clarity, carat weight and, most importantly, cut. The cut is further analyzed to include information about proportions, polish, and symmetry. The AGS grading scale (0-10) is used to measure cut, color, and clarity. The report also features a plotted diagram representing clarity characteristics and proportions.

AGS Diamond Quality Document

The Gold Diamond Quality Report

The Diamond Quality Report offers a complete grading analysis of cut, color, clarity, and carat weight in a simple report format. This report includes both AGS and GIA grading designations. The highest grade a diamond can receive for cut on the Diamond Quality Report is Excellent.

The Gold Diamond Quality Report
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