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Grading the 4Cs

Expert, unbiased diamond examination.

Expert, unbiased diamond examination.

Every diamond is unique.

However, every diamond evaluation is handled with the same care, expertise and strict guidelines. GIA offers the world’s most rigorous assessment of the 4Cs​.

Every diamond is unique.

However, every diamond evaluation is handled with the same care, expertise and strict guidelines. GIA offers the world’s most rigorous assessment of the 4Cs​.

Diamond Color Grading.

Viewed in a standardized environment, every diamond’s color is graded against masterstones. Multiple GIA graders independently evaluate each diamond and use our proprietary grading technology. The grade is not determined until there is consensus, and additional graders may be brought in until a determination can be made.

Diamond Color Grading.

Viewed in a standardized environment, every diamond’s color is graded against masterstones. Multiple GIA graders independently evaluate each diamond and use our proprietary grading technology. The grade is not determined until there is consensus, and additional graders may be brought in until a determination can be made.

Diamond ring
Photo courtesy of Sotheby's.

Diamond Clarity Grading.

Viewed with 10x magnification under standard conditions, multiple graders independently evaluate each diamond. First addressing any clarity enhancements or surface coatings, they document the diamond’s clarity, polish, and symmetry, while plotting the clarity characteristics on the diagram most representative of the diamond’s shape and faceting style.

Diamond Cut Grading.

Viewed using the GIA Cut Grading System, a proprietary computerized system designed to develop mathematical measurements, or metrics, to predict light performance based on more than 1 million modeled proportion sets to explore these components, followed by more than 70,000 human observations for nearly 2300 diamonds to validate and fine tune the metrics.

Half of a diamond with the other half of its facets outlined
Half of a diamond with the other half of its facets outlined

Diamond Cut Grading.

Viewed using the GIA Cut Grading System, a proprietary computerized system designed to develop mathematical measurements, or metrics, to predict light performance based on more than 1 million modeled proportion sets to explore these components, followed by more than 70,000 human observations for nearly 2300 diamonds to validate and fine tune the metrics.

Diamond images are for reference only and may vary based on screen size.

Diamond Carat Weight.

Weighed using the highest precision digital micro-balance available, every diamond is evaluated to the fifth decimal place, to the nearest hundred-thousandth of a carat to ensure accuracy, and then reported to the hundredths place.

Diamond images are for reference only and may vary based on screen size.

Expertise at your fingertips.

You don’t need to be a gemologist to purchase a diamond with confidence. You just need to know where to find one.

GIA is the trusted benchmark for diamond grading. Download the GIA App now to learn more about the 4Cs and look up GIA reports.

Expertise at your
fingertips.

You don’t need to be a gemologist to purchase a diamond with confidence. You just need to know where to find one.

GIA is the trusted benchmark for diamond grading. Download the GIA App now to learn more about the 4Cs and look up GIA reports.

GIA Report Check

Access your GIA Grading Report results using your GIA report number.