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.