Do more facets on a diamond produce better performance?
In a world where more is so often considered superior, it’s easy to assume that the more facets a diamond has, the more it will sparkle.
Facets are the flat surfaces between the edges of a cut and polished diamond. The modern round brilliant cut diamond consists of 58 facets, 33 on the crown (the top part above the girdle) and 25 on the pavilion (the part below the girdle). The round cut is known to have the most brilliance and sparkle of any diamond cut, hence its popularity. The facets are arranged in such a way that they radiate light outwards.
The function and purpose of the crown and pavilion facets is completely different.
Crown facets operate like windows to gather as much light as possible. Each individual facet has two independently operating parts.The windows are the open spaces through which light passes and is transformed into coloured light or dispersion. The frames are the lines and sharp intersections that separate the individual facets. Light is not absorbed by the frames, but is scattered and diffused. This is referred to as a diamond’s sparkle or scintillation.
The pavilion’s function is more straightforward. The mass of coloured light that has passed through the crown facets, is focused and directed back to the eye of the observer.
Simply put, there is no advantage to having more facets on a diamond. The number of facets a diamond has, affects the pattern of the reflections in a diamond rather than its overall brilliance. Diamonds with more facets have more smaller reflections instead of fewer larger reflections. Think of a window that’s been divided into several smaller windows within the same space. More windows means more frames which means less space for light to pass through.
The brightness of a diamond is a function of its proportions, polish and symmetry, not the number of facets it has.