The most common diamond cuts, as of 2014, include round, emerald, princess and radiant. A diamond’s cut is normally determined by the size and shape of the original, rough stone.
As of 2014, one-third of diamond engagement rings sold are round cut, making it the most popular cut in the United States. The princess cut, which has facets shaped like kites, was invented in 1980 and has remained a popular cut. An emerald-cut diamond is also known as a step cut, and its corners provide a way to secure the diamond to the setting. Radiant-cut diamonds are similar to emerald cuts, but their facets give them more sparkle.