Three-carat cushion cut diamonds are an increasingly popular choice for engagement rings. An antique shape, the cushion cut is a hybrid of Old Mine cuts. With less sparkle than a round brilliant, its softened appearance has a romantic style. A Near Colorless or Colorless grade is advised if you intend to select a white metal. The faint yellow in K or L graded diamonds is balanced by yellow gold. Setting your 3-carat cushion cut in a French-set halo or pavé diamond band will increase sparkle, while bringing a beautiful vintage feel.