Diamond Shapes

Round
By far the most preferred diamond shape, the round-brilliant cut is also the most optically brilliant because of its 360-degree symmetrical shape. A round brilliant is a great choice if you want the most sparkle and the most enduring classic shape. The round shape has been cut for centuries, but in 1919, Marcel Tolkowsky defined specific angles and proportions to yield the most brilliant diamond, which form the basis for the modern "Ideal" cut round-brilliant diamond. Round-brilliant diamonds are the only shape to have this ideal proportion defined. The round silhouette works with almost every mounting, from classic solitaires to the most avant-garde designs. Rounds can be set into four or six prongs, based on the design of the setting, or into bezel mountings (a metal band that runs around the edge of the diamond to hold it securely in the setting). In general, if the round brilliant has an Ideal cut or Very Good cut, you want the setting to have the least amount of metal around the stone so that it is held securely but does not cover up too much of the diamond and block light from entering the stone.

Princess
The princess cut is a modern classic of clean, square lines and beautiful sparkle. This shape is the perfect choice if you prefer a square or rectangular outline but want the brilliance of a round. Developed in the 1970s, the princess cut is now second only to the round brilliant in popularity. The cutting of this diamond combines the step-cutting of the emerald cut with the triangular facets of the brilliant cut and is cut with right-angle corners. Although most prefer a square outline, some stones are cut with a slightly more rectangular outline. The princess cut works beautifully as a solitaire but also looks great paired with side stones, especially trillions or smaller princess-cut diamonds. It is important to protect the more vulnerable corners with a V-shaped prong at each point.

Asscher
This elegant shape is a variation on a classic emerald cut, developed in 1902 by the venerable Asscher brothers in Holland. The Asscher cut is not a traditional choice but has gained deserved exposure recently because of celebrities wearing the cut. The uniqueness of this shape is defined by the pavilion, or bottom part of the diamond, that has a "scissor cut" with all facets step-cut down toward the culet, or point on the bottom. The blocked corners add to its geometric appeal, making the diamond appear almost octagonal. It is usually cut to a square outline as opposed to rectangular. This diamond shape is beautiful in a simple solitaire or in a setting that has simple geometric lines or side stones such as baguettes. Ideally, the setting for an Asscher cut should not hide the unique blocked corners.