A diamond cut refers to how a diamond has been shaped and faceted, which significantly affects its brilliance and overall appearance. The quality of the cut determines how well the diamond reflects light, influencing its sparkle and visual appeal. Common cuts include round, princess, emerald, and oval, each offering a unique look and style. The cut is one of the "Four Cs" of diamonds, alongside carat, clarity, and color. A well-cut diamond can enhance its beauty, while a poorly cut diamond may appear dull, regardless of its other qualities. The cut is graded on a scale from excellent to poor, guiding buyers in their selection.