The anatomy of a diamond refers to the distinct parts that make up a diamond's structure. The proportion of these features and the relationship they have with one another, determines the fire and brilliance of the stone.
Image source: Gemological Institute of America Inc.www.gia.edu
The top, horizontal facet of the diamond.
The table is the largest facet of the diamond and where most light enters and exits the stone.
The top section of a diamond extending from table to girdle which consists of star, bezel and upper girdle facets.
There are two important factors of the crown – height and angle.
The crown height can affect the brightness of the diamond and the dispersion of light – too tall or too short and the light will not be reflected into the pavilion effectively.
The angle of the crown will determine how much light is reflected into the pavilion in order for it to be reflected back up through the crown to the eye. Too shallow and the diamond will appear flat and ‘lifeless’.
The section that runs between the crown and pavilion.
The girdle defines the diameter of the diamond. A ‘medium to slightly thick’ girdle is ideal as if it’s too thin, the diamond is more susceptible to chipping and if it’s too thick, this adds too much unnecessary weight to the middle of the stone causing it to look smaller.
The bottom section of a diamond extending from girdle to culet.
Like the crown, there are two important factors of the pavilion to consider – depth and angle.
The depth of the pavilion is important as if it’s too shallow or too deep, the light will escape out the bottom or side of the diamond rather than reflecting back up through the crown.
The pavilion angle determines how much light reflects back up through the crown to the viewer’s eye.
The small facet or point at the tip of the diamond.
The size of the culet is expressed on an eight-step scale ranging from ‘None’ (a point) to ‘Extremely Large’. As a large culet can affect the bird’s eye view of a diamond, the smaller the culet, the better.