The cut refers to the proportions, finish, symmetry, and polish of the diamond. These factors determine the fire and brilliance of a diamond.

The cut is what gives the diamond its brilliance and fire; the angles and finish of any diamond are what determines its ability to capture light and flash in a fiery effect that makes diamonds so mesmerizing. Cut and proportions are extremely important features to consider when purchasing a diamond because they have the greatest influence on the sparkle and value of a stone. A diamond that is well cut reflects light from one facet to another and disperses it back through the top of the stone.  An ideal cut diamond is designed to get as much light reflected through the top or "table" of the diamond to create fire, brilliance and scintillation. If the diamond is too deep on the bottom, then light will be lost through the sides making the stone appear a little dull and causing what is commonly known as the "fisheye" effect. If it is too shallow, then it may appear dark.