The "radiant" shaped diamond can be either a square or rectangular shaped diamond, depending on the cut. The GIA refers to the radiant shaped diamond as a 'modified brilliant diamond' in its grading reports. Its square or rectangular shape tends to give the wearer the illusion of smaller fingers, making it ideal for those who wish to create this shortened effect.

It typically has 70 facets and a length to width ratio of 1 to 1.2-1.5. The square shape of this diamond requires it to be cut with greater depth. What this essentially means is that there must be greater weight in the pavilion than is normally found in most other shapes. This measure is necessitated by the need to maximize the light that can enter and be reflected back to the eye, and in so doing create the brilliance that should be found with the Radiant shape.

Properly cut, the facets of the radiant create the image of cracked ice within the diamond. Its cost tends to be 20% to 30% less than round shaped diamonds of the same weight. The four corners of the radiant diamond require that this diamond have prongs that will not only hold the diamond securely, but will also protect the corners from chipping. The radiant diamond is associated with energetic, spirited, social and exuberant personalities.