The Cushion Cut is a generic name for the Old Mine Cut developed before the turn of the century; these days the name" cushion" is often used for colored stones cut in this shape.

PHYSICAL CHARACTERISTICS AND CUTTING ISSUES
A Cushion Cut is a square or squarish-rectangular cut with rounded corners and 58 brilliant-style facets that resemble a pillow shape, hence the name.

A hundred years ago, when Cushion Cuts were first developed, diamonds were not cleaved into two pieces of rough, as they are today; they were ground down as a single stone and the resulting polished was lumpy and thick. Cushion Cuts have very thin girdles and bigger culets than today's full-cut diamonds.
Designers are requesting Cushion Cuts with big culets, but, in general, the smaller the culet, the better the stone. Older Cushion Cuts return light in blocky patterns; newly cut ones return light in needlelike patterns.