Of the 4Cs, cut is the most important characteristic because it has the greatest influence on a diamond's brilliance.
A diamond cut is a style or design guide used when shaping a diamond for polishing such as the brilliant cut.
Cut does not refer to shape (pear, oval), but the symmetry, proportioning and polish of a diamond.
The cut of a diamond greatly affects a diamond's brilliance; this means if it is cut poorly, it will be less luminous.
The better the cut grade, the more it will sparkle.