The "princess-cut" diamond, like the radiant, is another square or rectangular diamond shape. The princess shape is a relatively new diamond shape, created around 1980-81 in Los Angeles by Betzalel Ambar and Israel Itzkowitz, and is cut for maximum scintillation effect. The end result of the princess cut shape is a diamond that has the brilliance of the round brilliant, but with a different overall appeal.

It can have 49 to 78 facets, but generally has 78 facets for greater brilliance. Like other square shaped diamonds, the Princess cut must have a deep cut giving greater weight to the pavilion in order to bring out a greater amount of fire. A point to be careful of with the Princess-cut is the relatively slim girdle and pointed corners. If not set well these corners can be easily chipped.

One of the appeals of the Princess shaped diamond can be found in its cost savings. They can be as brilliant as a round brilliant, while being less expensive per carat. Yet another of the cost savings found with the Princess shape is found in its cut. In the cutting process the Princess shape follows the natural crystalline structure of the diamond more effectively than most other shapes. It is this following of the crystalline lines that allow cutters to retain higher yields of the rough carat weight than can be preserved in other diamond shapes, thus lowering the diamond's cost.

Like other square shapes, the Princess cut shape provides a good shape to help to diminish the appearance of long fingers. Compared to a round brilliant of similar weight, the princess cut, like the radiant, tends to be 20% to 33% less expensive. The setting for this shape is, again, similar to that of the setting for the Radiant. Like the Radiant, the Princess requires that V-shaped prongs are used to hold the body securely while protecting the corners. The Princess shape's lower cost, along with its attractive shape and brilliant shine, help account for its popularity for use as a solitaire engagement ring. The Princess shape is associated with the personality traits of independence, audacity and confidence.