The Cut and Shape of a Diamond

Polished diamonds are classified as round brilliant cut which refers to a round shape, or fancy cut which refers to any other shape.

There are three different types of cut:

The round brilliant cut which is the most familiar. The round brilliant diamond is the most popular diamond shape. Other examples of brilliant cuts are: oval, pear, marquise, and heart.
The elongated shape of the oval cut creates an illusion of lengthening the hand. The shape has a larger surface area than a round diamond of the same carat weight, giving the appearance of a larger stone.
The pear shape diamond resembles a teardrop and is a combination of the oval and marquise shape.
The marquise shape diamond is a similar to the oval stretched out with elongated ends. According to legend, King Louis the 14th wanted a diamond to be polished into a shape that resembled the shape of the smile of the Marquise of Pompadour.

The step cut has a row of facets that resemble the steps of a staircase and is usually four-sided and elongated. Variations of the same cut are square, emerald, and Asscher cut.

The mixed cut has both brilliant and step-cut facets. Cushions, radiant and princess cuts are mixed cuts