Cut: how the stone handles light
Shape is the outline; cut concerns the way facets and proportions interact with light. A well-executed cut can help a diamond look lively, while unsuitable proportions can reduce its appeal. Review the grading information that applies to the particular shape and report, and inspect the stone visually.
Colour: the degree of colourlessness
The D–Z scale describes increasing body colour in diamonds within that grading system. D, E and F form the colourless range. The setting, lighting, size and cutting style influence what a wearer notices. Fancy colour diamonds require a different colour assessment.
Clarity: characteristics inside and on the surface
Clarity grades describe inclusions and blemishes assessed under standard conditions. A higher grade is not a guarantee of a visible improvement in everyday use. Location, contrast and the type of inclusion matter alongside the label; ask about any durability concern.
Carat: mass, not diameter
One carat is 0.2 grams. Two stones with the same weight may present different face-up sizes because of their shape and proportions. Always read the millimetre measurements and compare the whole stone, not one grade in isolation.
Sources and further reading
This English edition draws on the source material referenced below.