Diamond Terms and Measurements

There are a number of terms and measurements which are used to describe various parameters of the round brilliant diamond cut. These are:

Table

The table is the flat octagonal facet on the top of the diamond. As a measurement, the diamond's table is expressed as a percentage of the width of this facet with respect to the overall diameter of the stone.

Crown

The crown is the upper half of the diamond. Crown height refers to the height of the crown, again measured as a percentage of the diameter of the stone.

Pavilion

The pavilion is the lower half of the stone. As a measurement, the pavilion depth is the depth of this region as a percentage of the stone's diameter.

Girdle

The girdle is that band of the stone between the crown and the pavilion. When a diamond is put into a prong setting, the prongs grip the diamond at the girdle. As a measurement, girdle is the thickness of this band divided by the diameter of the stone.

Culet

The very bottom point of the stone.

Star facet

These are eight triangular facets. One of each of their edges is one of the octagonal edges of the table.

Kite facet or Bezel facet or Crown main facet

All of these terms refer to the eight four sided facets in the crown which connect the corners of the octagonal table to the upper edge of the girdle.

Upper girdle facet

These 16 triangular crown facets abut the upper edge of the girdle and the lower edges of the bezel facets.

Pavilion facet or Pavilion main facet.

The eight pavilion main facets are four sided facets. The top corner of these facets touches the lower boundary of the girdle. These facets all come together at a point at the bottom of the stone, forming the culet. The pavilion main facets are similar to the bezel facets of the crown and each of the eight pavilion main facets lies directly below a bezel facet.

Lower girdle facet

The 16 lower girdle facets each have as one edge a pavilion main facet, as another edge, the lower bound of the girdle, and an adjoining lower girdle facet as the final edge.

Crown angle

The crown angle is the angle formed between the bezel facets and the girdle.

Pavilion angle

The pavilion angle is the angle formed between the pavilion main facets and the girdle.