A facet is a flat, planar surface ground onto a gemstone or diamond. Facets can be produced in many shapes and sizes and are generally arranged in groups depending on the shape and cutting style of the gem material.
Facets can be broken down into: Crown Facets and Pavilion Facets. The Table and Culet are also considered facets. The girdle of a stone can be faceted. The purpose of facets is to enhance the brilliance and scintillation of a gemstone.
The often large, horizontally orientated, central facet of a gemstone's crown which provides a window into the gemstone is called the Table Facet.
The term star facet is used to indicate the facets which border on the table facet. The origin of the name 'star facets' is obvious: together these facets form a star.
The Main Facets, or simply 'mains' which are also known as 'Kite Facets' lie in between the star and bezel facets.
Bezel facets, also known as the upper girdle facets, are the triangular facets which border on the girdle of a cut gemstone.
The pavilion of a faceted gem can be divided in Main facets and Bezel Facets just as with the crown. On the image on the right the Bezel Facets, or lower girdle facets, are the light colored ones and the Main Facets the darker colored ones.
Furthermore the pavilion harbors the culet, which in old cuts often consisted of a facet as well but has become a point in more recent times.