Anatomy of a Round Brilliant Diamond
BASIC DIAMOND ANATOMY
Modern round brilliant cut diamonds are composed of flat polished surfaces called facets. These facets are arranged in a specific pattern to receive light and to return light to a viewer’s eye. Round brilliants are usually composed of 57 facets that are divided into 3 main parts: Crown, Girdle, and Pavilion.
The crown is the top part of the diamond that sits above the girdle. Light enters a diamond through the crown facets. The crown is composed of bezel facets (crown mains), star facets, upper girdle facets (upper halves), and a table facet.
Table – Octagonal in shape, the table is the largest diamond facet. It sits at the top of the crown.
Bezel Facet – Also known as the “crown mains,” the bezel facets are diamond shaped and sit between the table and the girdle edge. There are 8 bezel facets on a round brilliant.
Star Facet – These triangular facets extend from the table to the upper girdle facets. There are 8 star facets.
Upper Girdle Facets – Also known as the “upper halves,” these triangular facets are closest to the girdle edge. There are 16 upper girdle facets.
The girdle separates a diamond’s crown and pavilion. Diamond girdles are often polished with tiny facets. Diamonds can also be found with girdles that have a frosted or slightly waxy appearance, finished but not faceted.
The pavilion is the bottom half of the diamond that sits below the girdle. The pavilion facets reflect incoming light that has entered through the crown facets. The pavilion is composed of lower girdle facets (lower halves), pavilion main facets, and an optional culet facet.
Lower Girdle Facets – Also known as “lower halves,” these triangular facets extend from the bottom of the girdle to the culet. There are 16 lower girdle facets.
Pavilion Main Facets – Kite or diamond shaped facets that often take on the appearance of arrows. There are 8 pavilion mains.
Culet – A small facet at the very bottom of a diamond. Most modern round brilliants do not have a culet. The bottom usually comes to a sharp point where the pavilion mains meet.