In an effort to help you understand the GIA Cut Grading System more fully, and to make the best use of it in your business, we provide these informative charts and booklets that summarize the system, and discuss each aspect of it.
Estimating a Cut Grade Using the GIA Diamond Cut Grading System
Explains the system, gives definitions, and displays the proportions listed on a GIA Diamond Grading report. It shows twenty-five example images of round brilliants — five in each of the five grade categories — and gives their proportion combination, values for additional parameters, and a short caption about why that diamond belongs in that grade category.
Large format chart, 32"h x 42"w (81 cm x 107 cm)
Poster - Estimating a Cut Grade (low res) (1.3MB)
Chart - Estimating a Cut Grade (high res) (10.5MB) (suitable for large format printing)
Chart in booklet form, 10 pages.
Booklet - Estimating a Cut Grade (6.34 MB)
(Revised December 2009)
Finish, Culet Size and Girdle Thickness: Categories of the GIA Diamond Cut Grading System
Explains and provides visual illustrations of the additional parameters that may limit the cut grade derived from the proportion combination: polish and symmetry, culet size, girdle minimum and maximum, and painting and digging out.
Large format chart, 32"w x 42"w (81 cm x 107 cm)
Poster - Finish, Culet, Girdle (low res) (1.3MB)
Poster - Finish, Culet, Girdle (high res) (9.35MB) (suitable for large format printing)
Chart in booklet form, 12 pages.
Booklet - Finish, Culet, Girdle (high res) (7.65MB
GIA Cut Grade Estimation Tables for Standard Round Brilliant Cut Diamond
Explains how to locate a particular proportion combination, and determine whether it is close to a boundary in the cut grading system. It also discusses how to use Facetware online to obtain a more accurate estimate of a cut grade.
Full-color, 8 page booklet.
Booklet - Cut Estimation Tables (low res) (2.94MB)
Booklet - Cut Estimation Tables (high res) (11.1MB)
For additional information about these charts and booklets and how to use them, download a cover letter from Tom Moses, senior vice president, GIA Laboratory and Research, to learn more.
How to Use the GIA Cut Grading Charts