- Cut
Cut evaluates how proportions and finishing influence light return. For round brilliants, reports may include a cut grade such as Excellent, Very Good, or Good. Fancy shapes are assessed differently, so compare proportions and appearance rather than relying on one label.
- Colour
The D-to-Z scale describes the absence or presence of yellow or brown colour in many diamonds. Metal colour, setting style, diamond shape, and personal preference affect what is visible. A higher letter grade is not automatically the best use of a budget.
- Clarity
Clarity describes internal and surface characteristics observed under controlled grading conditions. Grades range from Flawless through Included. Visibility, position, durability, and the size of the diamond matter more than the abbreviation alone.
- Carat
Carat is weight, not a direct measurement of face-up size. Shape and proportions can make two diamonds of the same weight appear different in diameter, length, or presence.
Balance the grades
Begin with the shape and visual character you prefer. Then compare cut and proportions, choose a colour that works with the metal, and inspect clarity at normal viewing distance. Carat comes last when it is treated as a weight target rather than the whole decision.