The ideal girdle, measurements and cut for a princess-cut diamond depend on your personal preference and what type of diamond suits your hand profile and design. Measurement can vary from one princess-cut diamond to the next due to its cut. The cut, depth and girdle are the most important factors that determine the overall look of your princess-cut diamond and ensure the correct proportions and symmetry. Princess cuts with uneven sides or unequal proportions and non-symmetrical ones are less attractive.
Choose a total depth between 65% – 75% for the best balance of brilliance to diamond size. For a squared princess-cut diamond, stick to a length-to-width ratio of 1.05:1 or less. For an excellent cut, a depth of 64% – 75% and 67-72 table percentage will result in a very thin – slightly thick girdle. For a good cut, 56 – 58 % or a 76-82 table percentage and a 58-63.9 or 75.1-90 depth percentage will result in a very thin to thick girdle.
The symmetry of the princess diamond facets helps find a desirable balance of light and dark areas, avoid the pavilion bulge and create the beauty of the cut. Symmetry is easier to find on the larger facets of a princess-cut diamond. To ensure symmetry, the left and the right half of a princess cut should be the same, with no extra facets where the points of the facets meet. The bottom two halves should also be symmetrical. To prevent the pavilion bulge that makes the stone look dark and adds extra weight, you should avoid a steep slope from the girdle to the culet from the side. Instead, the pavilion should slope gently.