The four C's of diamonds stand for Carat, Cut, Clarity, and Color. Carat weight is how a diamond is measured and is the size of the diamond. Cut is how well the diamond has been cut and includes the height, depth, angles, and other factors. Clarity is how many blemishes or inclusions and is judged on a 6 point scale from included to flawless. Color is judged on a scale from D (no hue) to Z (a yellow hued diamond).