"Although everyone thinks they would want a 2-carat diamond ring, sometimes it would look funny if the person's fingers are too thin," Shai Barel, director of strategic partnerships for Brilliance, tells CNET. "The same is true with the shape of the ring. A 1-carat round-cut diamond looks bigger than a 1-carat in any other shape. Providing customers with the ability to see and feel what they would like to purchase is golden."