When people think of cut, they often think it’s the shape of the diamond. But, it’s about how light is returned due to a diamond’s facets. Cut is responsible for brilliance, fire, and scintillation of a diamond.
Brilliance = combination of all of the white light reflected internally and externally
Fire = a scattering of light into a play of color
Scintillation = a diamond’s sparkle
For the best results, proportions of its facets, symmetry, the relationship of its weight to its diameter, girdle thickness, and quality of its polish have to come together in just the right way.