Anatomy of a Round Brilliant Diamond

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.
 

Basic Diamond Anatomy

Crown Girdle and Pavilion of a Diamond

Crown

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, bezel, Star and Upper Girdle Facets of a Diamond

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.

Girdle

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.

Pavilion

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.

Culet, Pavilion and Lower Girdle Facets of a diamond

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.