The 4Cs of Lab-Grown Diamonds

GIA developed the 4Cs — cut, color, clarity, and carat weight — as a common language for describing diamond quality. The same four categories are used when a laboratory-grown diamond is graded.

Use the grades as a comparison framework, then inspect the exact report, measurements, proportions, and stone video. A grade does not replace judging the individual diamond or confirming that the selected stone matches the product configuration.

Cut describes how proportions, symmetry, and polish influence brightness, fire, scintillation, weight ratio, and durability. Color, clarity, and carat weight describe different characteristics and cannot compensate for a visibly weak cut.

GIA's overall cut grade applies to standard round brilliant diamonds and uses five categories from Excellent to Poor. Fancy shapes require a broader review of their measurements, proportions, polish, symmetry, and face-up pattern because a single cross-laboratory label is not a direct substitute for that evaluation.

For any selected stone, compare the report with the actual images or video. Length-to-width ratio describes outline preference, not quality by itself, and the right range depends on the shape and design brief.

Laboratory terminology can differ, so do not translate one lab's grade into another lab's grade without reviewing both standards and the individual report.

GIA's D-to-Z color scale describes the absence of color, beginning at D. Diamonds with color outside that range may be evaluated under a separate colored-diamond system.

Color is graded under controlled viewing conditions. The visible result in a finished ring also depends on stone size and shape, lighting, viewing angle, and the setting metal.

Compare the actual stone in neutral light and, where possible, against the intended metal. Use the report grade to narrow the choice, not to predict an identical face-up appearance in every setting.

Clarity grades describe inclusions and blemishes observed by a skilled grader under 10× magnification. The scale runs from Flawless through Included, with several categories between them.

"Eye-clean" is not a laboratory grade. Visibility without magnification varies with the inclusion's size, type, location, relief, and the stone's shape and size.

Brilliant and step-cut facet patterns can reveal inclusions differently. Review the plot and video for the specific diamond rather than applying a universal clarity floor to every shape.

If an inclusion is near a point, corner, or girdle, ask whether it affects durability or setting placement. The grading report is the starting record; the individual stone still needs visual review.

Carat is weight, not size. One carat equals 0.20 grams. Two stones at the same carat weight can have different face-up dimensions because their depth and proportions vary.

The round dimensions below are approximate visual references, not selection specifications. Fancy-shape dimensions vary too widely for one carat-to-millimeter conversion, so compare the exact length and width on the report.

Finger size and band width change the visual relationship, but they do not prescribe a correct carat weight. Sula's standard center-stone selection starts at 1.5ct; the 1ct row remains as a comparison reference.

Confirm whether a listing uses center-stone carat weight or total carat weight across multiple stones before comparing products.

Selected-stone check

Verify the actual stone, not a house-wide assumption

Current availability, report laboratory, grades, and inscription details can vary by selected stone. The product and stone records shown for that selection are the source of truth.