The cut of a diamond is responsible for the quality of a diamond’s sparkle. If a diamond is cut poorly, it will appear dull even if it has a high colour and clarity grade. If a diamond is cut well, it will reflect and refract light for maximum brilliance, sparkle and luminosity.
There are three factors that determine a diamond’s cut:
the level of precision on the angles and proportions of the stone.
the symmetry where the facets align and intersect.
the polish on the finish of the stone.
I only use ‘excellent’ and ‘very good’ grade cuts.