The 4Cs
Cut, carat, colour and clarity provide a shared language for describing a polished diamond. They help you compare stones, but no factor should be read in isolation.
Cut
Cut governs how the proportions, angles and finish of the facets handle light. GIA grades the cut of a standard round brilliant from Excellent to Poor. Other shapes, often called fancy shapes, do not receive an overall cut grade from GIA.
Carat
Carat is a measure of weight. One carat equals 0.2 grams. Weight alone does not tell you how large a diamond will look from above; shape, proportions and setting all affect its appearance.
Colour
The D–Z colour scale describes the degree of colourlessness in diamonds within the normal colour range. D is colourless, and the scale continues towards an increasingly visible yellow or brown tint. Fancy-colour diamonds are assessed under a separate system.
Clarity
Clarity describes internal inclusions and external blemishes. The grade is determined at 10× magnification and considers factors including each characteristic’s size, position and visibility.
How to use the 4Cs
- First choose the shape and appearance you like.
- Compare diamonds of a similar shape and carat weight.
- Consider cut, colour and clarity alongside the actual stone.
- Read the grading report and verify its number with the issuing laboratory.
- Confirm the price of both the diamond and the setting.
The 4Cs describe quality characteristics. They do not automatically establish a stone’s monetary value, ethical origin or environmental impact.
Compare diamonds or book a consultation if you would like to review a report with us.