A diamond’s beauty,
Refers to the angles and proportions of a diamond. Cut also refers to shape: round, square, pear, or heart. A round diamond is the most brilliant of all diamond shapes.
Refers to the degree to which a diamond is colorless. Diamonds range in color from icy winter whites to warm summer whites.
Refers to the presence of flaws or "inclusions" in a diamond. An inclusion in the middle or top of a diamond could impact the dispersion of light, sometimes making the diamond less brilliant.
Carat is a measure of weight not size. Cut and mounting can make a diamond appear larger (or smaller) than its actual weight.