Diamond Anatomy: Diamond Parts and Facets

The Diamond Crown stretches from the top of a diamond or table to a diamond’s side or girdle. Some gemologists measure the Crown from the corner of the table to girdle valley or dip, while others measure it to the girdle bezel or highest point of the girdle. The crown can consist of Brilliant cuts or Step cuts.

A Facet is a cut surface in a diamond.

The top of a diamond or Table is the largest facet. This facet acts like a window into the inside of a diamond. The size of the Table determines the look of the stone: the bigger the Table, the greater the brilliance or white light return and the lesser the fire or colored light return; the smaller the Table, the greater the fire and lesser the brilliance. Surrounding the table in brilliant cuts are crown facets. At the bottom are pavilion facets, which act like mirrors reflecting light back through the upper facets. A Round Brilliant diamond has 57 facets not counting the cutlet.

Picture: Verena Pagel-Theisen, Diamond Grading ABC: Handbook for Diamond Grading, 1980, p.154

If you look at the crown, excluding the bezel and upper girdle facets in brilliants, you'll notice that the star facets and the table make a design that looks like two staggered squares. Diamond Tables that are very small as in “ideal” Round Brilliant cuts make the tables appear bowed inward, while tables that are too large can look bowed out. You’ll be able to judge the table by the plot on the grading report.

Star Facets in brilliants: next to each octagonal edge of the Table are eight facets that form an eight sided star; thus the name.

Bezel Facets in brilliants: diamond osr kite shaped facets that extend from the corners of the Table to the Girdle or side.

Upper Girdle Facets in brilliants: the sixteen crown facets that run around the perimeter or girdle edge. Each almost forms a right angle with the girdle.

Main Pavilion Facets in brilliants and mixed cuts: the eight long four-sided facets that extend from the bottom point or culet to the girdle.

Culet: when the point at the bottom of a diamond is removed to prevent chipping. Many non-certified JA bench jewelers end up chipping center diamonds when trying to set them. It is always a good idea to ask for whoever’s setting the diamond to provide proof of higher JA certification. A Cutlet that is too large can produce a circular shape in the middle of the Table.

A Girdle is the side of a diamond and measured as its perimeter.  AGS Labs grades the Girdle height by the valleys while HRD grades the Girdle by the bezel. The Girdle can be faceted, polished, or rough.