The cushion cut diamond  combines a square cut with rounded corners, much like a pillow (hence the name). This classic cut has been around for almost 200 years, and for the first century of its existence was the most popular diamond shape (similar to round cut today)! Until the early 20th century, the cushion cut diamond was the de facto diamond shape.This unique shape has been popular for more than a century. Cushion-cut diamonds (or "pillow-cut" diamonds) have rounded corners and larger facets to increase their brilliance.