A Brief History of Cut Diamonds
By Gary Dutton
Diamonds were probably first found in India as loose stones associated with the sand and gravel of riverbeds. For centuries they were thought to posses magical powers because of their hardness and luster, and were kept, uncut, as sacred objects or important treasures of state by the religious and political leaders of the day. Being regarded as talismans, it was thought that they would lose their powers if they were altered in any way.
It wasn’t until the 11th century that diamonds were first worn, in their uncut form, as adornments. However, with the use of diamonds in jewelry, sometime in the 13th century, it became known that a diamond’s appearance could be enhanced by grinding and polishing along the four octahedral faces of the rough crystal. This was achieved by polishing with diamond dust at angles varying slightly from those of the original octahedral faces to form a point cut.
The table was the first major facet to be fashioned on a diamond crystal. Thus, the table-cut diamond was formed by grinding down the top octahedral point to form a square facet using a recently discovered technique called bruting. This table facet was then finished off by polishing with diamond powder.
Later, table-cut diamonds were further modified by adding a smaller facet to the lower octahedral point to form a culet at the bottom of the stone. These culets were often large, as much as half the size of the table, and designed to reflect light and add brightness to the diamond.
With time, many of the older point-cut stones were converted to table cuts because of their popularity. Subsequently, table cuts themselves were further modified by adding eight narrow facets, one to each edge of the table and pavilion, in order to improve the brilliance of the stone.
A major advance in faceting came about with the introduction of the polishing wheel in the middle of the 14th century. This led the way for manufacturing brighter diamonds with increased facet pattern complexity. In this same era the rose cut appeared. Its shape is basically flat and usually circular, with a faceted, domed top and plain bottom. This cut was common until the early 1900’s.
By the mid-seventeenth century the single cut emerged. This design was formed by producing a more rounded overall shape with an octagonal-shaped table and eight facets on each the crown and pavilion. This cut eventually evolved into the brilliant cut with the complete rounding of the girdle and the application of additional facets to the crown and pavilion.
The term “brilliant-cut” was coined at the end of the 17th century and was represented by several forms of faceted diamonds based on the shape of the commonly found octahedral form of the rough crystal. These cuts were round, rounded or cushion-shaped in girdle outline. During the early 18th century, Brazil, the new center of world diamond production, gave rise to the cushion-shaped old-mine cut, a forerunner of the modern brilliant cut having 33 crown and 25 pavilion facets, the same 58 facets as today’s round brilliants.
With the 19th century came the rounded cuts like the old European cut, also having a total of 58 facets of the same type as today’s round brilliants. Old-mine and old European cuts are deep-cut with small tables and relatively large culets.
The early modern Tolkowsky brilliant cut emerged with Marcel Tolkowsky’s published thesis entitled, “Diamond Design: A Study of the Reflection and Refraction of Light in Diamond”, in 1919. This was a theoretical work describing the best proportions of a round brilliant diamond which would provide a balanced return of brilliance and dispersion. As a result, many cutters were led to fashion many of the larger, high quality goods in the range of these proportions. These proportions are also sometimes called the “American Ideal Cut“, even though the work originated in Europe.
Today’s modern round brilliant cut diamond, produced largely since World War II, differs in several ways from the Tolkowsky cut. The Tolkowsky brilliant had a larger culet, visible through the table, whereas today’s round brilliant has either no culet, or a very small culet. Also, the table size range is larger in today’s round cuts (about 53-57%, as a percent of the stone’s average diameter), but still include Tolkowsky’s calculations which called for a 53% table.