The most popular diamond shape traditionally used for a diamond engagement ring is a round brilliant cut. A round brilliant diamond is cut in a round shape at the top and the rest of it is cone shaped to maximise the return of light. Because it is the same shape all around, it has a large return of light and is the most brilliant of diamond cuts. Perfectly proportioned, it counts for the majority of diamond sales today.
Of all diamond shapes, round brilliant has been the most researched by diamond cutters. Introduced in the 17th century with only 17 facets, and over the last three hundred years diamond cutters have used advanced light theories and maths to develop the round brilliant diamond that we know today with an average 58 facets.
Round Brilliant are not to be confused with round diamonds which are also desirable and valuable, but not cut with the same detail and consideration in the facets and return of light.