The cut of a diamond refers to the shape of the individual gemstone. Diamond cutters consider the best use of a diamond's superlative material properties such as the shape and size of the crystal when selecting a precise cut. The diamond cut chosen constitutes a more or less symmetrical arrangement of facets which together modify the shape and appearance of the diamond crystal. The history of diamond cutting dates back to the Middle Ages when it was done by hand; a very primitive process by today's standards. Today's diamond cutters utilize advanced technology in addition to their own expertise to determine the best shape for a particular stone with the intent of creating the most attractive, glittering product while wasting the least amount of the gem during the creative process.
The most popular diamond shape is the round brilliant-cut displayed in the diagrams here on this page. The round brilliant's facet arrangements and proportions have been perfected over the centuries by both mathematical and observational analysis. Also popular are the fancy cuts, which come in a variety of shapes and were derived to a certain extent from the round brilliant. The princess-cut has become a very popular choice for engagement rings over the past decade as well as the radiant-cut.
A diamond's cut is evaluated by trained diamond graders who give higher grades to stones whose symmetry and proportions most closely match the particular ideal utilized as a benchmark standard.