These pages show how to read a diamond grading report from top to bottom: what each field means, how to check that a report belongs to the stone, and where an IGI report differs from a GIA one. Each page teaches the GIA report first and then notes what IGI does differently. You try each point on the report that our 3D Gemstone Simulator writes for the stone on screen, and you rebuild a round from its proportions in our Cut Grading Tool.
New here? Start with How to read the proportion diagram on a diamond report.
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1 · Article
What a diamond grading report is, and what it isn't
What a report records, why it is not an appraisal, GIA's report types and the five parts of any report.
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2 · Article
The ID section of a diamond report: number, shape and measurements
Report number, shape, measurements and carat: how to check that a report belongs to the stone in front of you.
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3 · Article
The grades on a diamond report: color, clarity and cut
How a report writes color, clarity and cut, what the asterisk means, and how to spot a grade line that can't be real.
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4 · Article
What "ideal cut" means on a diamond report
Where "Ideal" appears on IGI and GIA reports, IGI's Ideal band, and why Ideal and Excellent aren't the same thing.
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5 · Article
Polish, symmetry and fluorescence on a diamond report
What polish and symmetry describe, how they cap the cut grade, and why fluorescence is not a grade.
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6 · Article
The clarity plot: how to read the inclusion map on a report
The plotted diagram, the key to symbols, and what the Dossier gives instead of a plot.
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7 · Animated explainer
How to read the proportion diagram on a diamond report
Every number on the proportion diagram, and how to rebuild a round and its cut grade from them.
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8 · Article
Comments, treatments and lab-grown origin on a diamond report
What goes in Comments, which treatments are graded, and how a report shows lab-grown origin.
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9 · Article
How to read a diamond grading report, start to finish
A six-step checklist for any diamond report, the IGI differences in one table, and five errors to find.
Quick quiz
Every lesson ends with a few questions. Want more? The Reading a grading report quiz covers the whole topic, with the answer and the reason after each question.
Cuts in this topic
We sell the files of these cuts: 3D models and cutting files, with a personal-use license.
