The “C” with the most impact on the value and brilliance of your diamond is CUT
People often think that a diamond’s “cut” is referring to its shape (round, princess, oval, marquise, pear), but a diamond’s cut grade is actually a measurement of how well the diamond reflects light. The better the cut grade, the more brilliant and sparkly your diamond will be. It takes incredible skill to fashion a diamond with precise symmetry, polish, and proportions, which gives the diamond a brilliance unmatched by any other gemstone.
Round Brilliant Cut Scale
EXCELLENT, VERY GOOD, GOOD
FAIR, POOR
TIP: The cut grade weighs heavily when determining diamond price, sometimes as high as 40%. ALWAYS ask for a cut grade when shopping for diamonds.
Fancy Shape Light Performance Scale
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Note: With all fancy diamond shapes (anything other than round), the cut grade is defined on a scale of 0-10 in light performance, 0 having the highest light performance or least loss of light, and 10 being the lowest light performance or most loss of light. Though this scale is widely used, fancy shaped diamonds are not reported on using this grading system.