The brilliance, fire, and scintillation of a diamond rely heavily on its cut. When a diamond is optimally cut it becomes radiant; it catches, reflects, and plays on light. The diamond sparkles and shimmers like it has a life of its own. But when the diamond is cut poorly, it looks lifeless and dull.
Of all the diamond cuts, the round cut is the most popular. Approximately 80% of the diamonds sold globally are cut this way. With 58 facets, the round cut diamond sparkles the most of any cut. Due to its many facets, light is properly reflected and its brightness is maximized. The round cut shape resembles that of a cone which increases the light return through the top of the diamond.
The round cut is the most expensive cut. Although extremely popular, this is not the reason for the price. Round diamonds lose much of their original carat weight during cutting and polishing, more than any other type of cuts. As a result, the loss of weight is dramatic and is rarely less than 50%. That is why this cut costs the most.
A round diamond that is cut ideally is the most beautiful and brilliant of cuts. This is why round diamonds are often set in four-prong solitaire engagement rings. The use of a single stone in this timeless setting showcases the brilliance of the diamond.
This type of cut rose in popularity during 1919. Marcel Tolkowsky wrote and published his thesis called “Diamond Design: A Study of the Reflection and Refraction of Light in Diamond,” which described the ideal proportion of the round cut in terms of maximizing a diamond's brilliance and fire. Over the years, the round cut has evolved tremendously. Tolkowsky's original guidelines have since been modified as diamond cutting technology has evolved. Today, diamond manufacturers have produced and marketed incredibly brilliant round cuts.
The round cut is the most versatile of all cuts when it comes to style and value. Having more fire and brilliance than any other shape, this cut provides the excellent balance between cut, color, and clarity grades.