– Color, Clarity, Cut, and Carat Weight – collectively known as the “Four Cs” – form the core factors that gemologists evaluate in a GIA diamond grading report. Color appears on a precise D–Z scale. On this scale, D represents a completely colorless diamond and Z indicates a diamond with increasing tint, typically yellow or brown. Clarity assesses the presence of internal characteristics (inclusions) and external characteristics (blemishes) and assigns a clarity grade that spans from Flawless to Included. Cut evaluates how a diamond’s facets interact with light. In addition, cut considers proportions, symmetry, and polish to determine how much brilliance, fire, and scintillation the diamond displays. Carat Weight measures the diamond’s weight to the hundredth of a carat. Also, the report records this measurement exactly as weighed.
Each full GIA Diamond Grading Report presents these Four Cs along with a detailed, plotted diagram of the diamond’s clarity characteristics. This diagram maps the type, size, and location of inclusions and blemishes within the diamond. As a result, it gives a visual “fingerprint” that helps jewelers and owners identify the stone. Moreover, this diagram also helps readers understand how the grader determined its clarity grade. The report also provides a graphic representation of the diamond’s proportions. This is often shown as a profile diagram with measurements such as table size, depth percentage, crown and pavilion angles, and girdle thickness. Together, these factors influence the diamond’s overall cut quality and appearance.
The GIA Diamond Dossier presents the same essential grading information on the Four Cs but omits the full graphical clarity plot. Instead, the dossier focuses on the written clarity grade and key measurements. This makes it a more streamlined report option. Both types of reports follow strict laboratory standards. The GIA laboratory issues diamond grading reports only for loose, natural diamonds (not mounted or lab-grown) in the D-to-Z color range that weigh 0.15 carats or more. This policy ensures consistent, objective grading. It is based on internationally recognized GIA criteria.
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