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. Its 58-facet cut, pided among its crown (top), girdle (widest part) and pavilion (base), is calibrated through a precise formula to achieve the maximum in fire and brilliance. 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.  Every Sitaragem round-brilliant gemstone is hand cut to “Ideal” proportions and possesses the “hearts and arrows” pattern that brilliantly illuminates the inner sparkle and passionate fire.

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. With 104 sparkling facets, 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.

The Emerald-cut is among the most classic of diamond shapes. The Emerald cut can be absolutely stunning. Because of it’s long lines, it tends to be less fiery than a "Round brilliant" cut, but it also tends to have broader, more dramatic flashes of light. The trim lines of emerald cut diamonds lend an elegant, sophisticated air to both the simplest and most elaborate ring settings. It features 27 facets and its clean lines come from step-cutting, or parallel line facets. It is always cut with blocked corners and is usually cut to a rectangular outline, although a few are cut to be more square.

The Trillion cut is a dramatic cut that makes a bold statement. It was developed in the 1970s as a variation of the radiant cut, combining step-cutting and brilliant faceting. It features 58 facets, aligned in a geometric shape. While often used as side stones, this cut is rarely used for the center diamond, so it is somewhat scarce in larger sizes. The triangular shape needs to be considered with the style of mounting and would probably go best in a simple solitaire or geometric setting that works with the unique shape. The trillion cut will require a special setting that has V-shaped-prongs to protect the corners of the stone.

The Square Emerald (commonly referred to as an Asscher or Royal asscher) 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. The newest version of the Asscher cut is known as "The Royal Asscher". It has 74 precisely placed facets that truly reveal an unsurpassed depth and beauty. This diamond shape is beautiful in a simple solitaire or in a setting that has simple geometric lines or side stones such as baguettes. The Asscher gem is very fashionable and makes dramatic engagement and anniversary rings.

The Pear cut is a beautiful, feminine diamond shape with a rounded end on one side and a tapering point at the other. It is a hybrid cut with 58 facets, combining the best of the oval and the marquise. It is lovely as the center stone in a ring or outstanding as a pendant or pair of drop earrings. As with many fancy shapes, length-to-width ratio should be considered. Good symmetry is a must for pear-cut diamonds. This will ensure that light is reflected evenly, especially in the point. The asymmetrical shape should be considered when setting a pear cut, which looks beautiful as a solitaire, or with side stones, especially smaller pear-cut stones or baguettes.

The Heart-shaped cut is the most romantic of diamond shapes ultimately revealing a sparkling symbol of love. It is similar to the pear shape but has a cleft in the rounded end that forms the lobes of the heart. It features 58 facets and the complexity of the shape requires skilled cutting to ensure proper brilliance. Symmetry is a big consideration for this shape, as the outline needs to have a pleasing, obvious heart outline apparent in the setting. The lobes should be rounded (not pointed) and clearly defined.

The Oval cut is most similar to a round-brilliant cut and combines the round’s sparkle with a flattering, elongated outline. It makes a good choice for someone who wants a unique shape but loves the fire and brilliance of a round diamond. Its design is even and perfectly symmetrical, with 58 facets to show off its brilliance.

The Marquise cut is a regal, elongated shape with tapering points at both ends. Inspired by the fetching smile of the Marquise de Pompadour and commissioned by the Sun King, France’s Louis XIV, who wanted a diamond to match it. It is gorgeous when used as a solitaire or when enhanced by smaller diamonds. Its shape tends to flatter the finger, making it appear longer. This cut features 58 facets and is considered to be very feminine. When choosing a marquise cut, the length-to-width ratio should be considered. Usually a ratio of 2:1.0 is preferred, meaning that the length of the stone should be about 2 times the width of the diamond.

The Cushion cut is an unusual diamond shape and an interesting alternative to an oval- or princess-cut diamond. Because these are relatively rare, this shape is for someone who wants something few people possess. The modern cushion shape is based on an antique cushion cut, which is a combination of round and square outline with a softened square or "pillow" shape. With its 104 sparkling facets, it shines and shimmers even in the lowest levels of light. A cushion-cut may be squarer with length and width in equal proportion, or may have a slightly elongated outline, depending on the inpidual stone and the wearer’s preference. As a solitaire, it makes a statement and also looks wonderful paired with side stones such as baguettes.

The Radiant cut is a beautiful combination of the classic emerald cut and the sparkle of the round brilliant. The radiant cut is similar to the princess cut but is usually (though not always) a more rectangular outline and has blocked corners like those of an emerald cut. With 104 facets, it maximizes the effect of its color refraction and sparkle. The cutting is a combination of the step-cutting of the emerald-cut diamond with some triangular faceting of the brilliant cut. The radiant cut is dramatic as a solitaire but also looks great paired with side stones such as baguettes, trillions, or princess shapes.