Learn the secrets

Preface | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8

Step 7: Understanding laboratory diamond grading reports: GIA versus AGS

Within the diamond trade there are numerous organizations who have established businesses, some for profit and some non profit, that are in the business of assessing the value of diamonds for both consumers and businesses. These organizations or laboratories produce certificates or grading reports that reveal the quality, and hence value, of a diamond. Among the most reputable organizations for the grading of diamonds are the GIA and the AGS. We would like to compare and contrast these two organizations and reveal the differences in the certificates that they produce………

The most obvious differences between the GIA Certificate and the AGSL Diamond Quality Document is in how each organization grades a diamond. The GIA Certificate only measures or grades the dimensions of a diamond. For example, a diamonds width, height or depth percentage. The AGSL Certificate reveals more information about the shape of a diamond. The AGSL Diamond Quality Document reveals information about the “cut” of a diamond such as the CUT GRADE, DIAMOND PROFILE, CROWN ANGLE, PAVILLION DEPTH, CROWN HEIGHT, PAVILLION ANGLE and TOTAL DEPTH PERCENTAGE.

STEP 7: Identifying the exact numbers found on a GIA Grading Report that determine IDEAL CUT for all shapes of diamonds :

Grade: IDEAL CUT Shape: Round Brilliant Table: 55% - 57% Depth: 61% - 62% Polish: Excellent – Very Good Symmetry: Excellent – Very Good Grade: Good Shape: Round Brilliant Table: 53% - 57% Depth: 61% - 62.8% Polish: Excellent – Very Good Symmetry: Excellent – Very Good ETC…….

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