Refers to the angles and proportions of a diamond. 

The cut (or ‘Make’) of a diamond is a most important feature. Cut refers to the angles and proportions a skilled craftsperson creates in transforming a rough diamond into a polished diamond. Even if a diamond has the highest colour and clarity, a poor cut will result in the diamond having a dull brilliance.

A well proportioned diamond follows strict mathematical proportions. The light entering the diamond from the top will be internally reflected from one facet to another within the diamond before being refracted back through the top, and returned to the eye of the observer, giving the stone maximum brilliance, scintillation and fire.

A diamond can be cut to retain maximum weight and to create the illusion of size, but this results in a loss of brilliance. If cut too deep, light will escape through the bottom facets and the centre of the diamond will appear dark. If the stone is cut too shallow, the light will also escape through the bottom facets giving the diamond a watery or glassy appearance. A well cut diamond will internally reflect light from one facet to another and disperse and reflect it through the top of the stone, maximising the brilliance as well as the fire of the stone.

Cut can also refers to shape – round, princess, pear, oval or heart for example. Since a round diamond is symmetrical and capable of reflecting nearly all the light that enters, it is the most brilliant of all diamond shapes.