Diamond cutting, the art of fashioning and polishing faceted gems from rough diamond crystals extracted from the Earth, has been practised for thousands of years. The history of diamond cutting originated in India where diamonds were first found and fashioned.
The brilliant style is the predominant facet arrangement. For this cut, the top of the diamond (crown) has a central large table facet surrounded by a series of smaller triangular and four-sided facets. The bottom of the gem (pavilion), normally hidden from view when set in jewellery, has a series of thin triangular and four-sided facets leading to either a central point or tiny culet facet. This combination of shape and cutting style is called the modern round brilliant.
In Europe the brilliant style developed from the 17th century. The outline of the brilliant cut diamond was determined by the basic profile of the diamond crystal. Many crystals have a rounded rectangular outline so the brilliant cut diamonds fashioned until the mid-19th century had this cushion-shaped outline. A brilliant cut diamond having a cushion shaped outline is called today an OLD MINE CUT. Later, improvements in the technology of diamond cutting machines meant the outline of a fashioned diamond could be made to a perfect circle. Brilliant cut diamonds with round outlines fashioned at this time are called OLD ENGLISH CUT diamonds (in the U.S. the term is OLD EUROPEAN CUT)
Both Old Mine Cut and Old European Cut (collectively known as OLD CUT Diamonds) have a smaller table facet size, a larger culet size and are deeper than modern round brilliant cut diamonds.
Predating the brilliant cut was the rose cut, an antique style of round to rounded shape. The diamond has a flat base and tiny triangular facets ordered around a central point on its top. Rose cut diamonds are rarely fashioned today.
As diamond cutting has been a traditional craft, the shift from cutting old cut diamonds to the modern round brilliants was gradually spread over many decades. Terms such as ‘Victorian cut’, ‘Edwardian cut’ and ‘transitional cut’ describe the round brilliant styles fashioned during different decades of this change.
In the early 20th century, knowledge of how light interacts with diamond through reflection and refraction increased and a better understanding was attained of how the sizes and symmetry of the assorted facets of the diamond and the proportions of the top (crown), edge (girdle) and bottom (pavilion) influence the beauty of the diamond. As a consequence, new designs for the symmetry and proportions of round diamonds were formulated and today we see a consistent pattern for the modern round brilliant cut diamond.
Any diamond having an outline that is not circular is called a fancy shape. Such diamonds are fashioned from irregular shaped crystals to yield the best sizes. Popular fancy shapes are the Princess cut, Emerald cut, Asscher cut, the Radiant and the Cushion brilliant.