The Weight of a diamond is measured in carats. One carat is divided into 100 parts called "points," 1 ct. = 1.00; 1/2 ct. = 0.50.. The value of two diamonds of the same weight can vary greatly depending on the color, clarity, and especially the cut. To the right are two identical pieces of rough (uncut) diamonds, each of the same quality and value.

Example 1: From one piece of rough a diamond has been cut to ideal proportions, retaining a weight of one carat. The light is totally reflected through the top.

Example 2: The second piece of rough has been "spread" in its cutting, resulting in a diamond weighing approximately 1.40 ct. Note: The girdle is thicker, the table is much larger, the angles are exaggerated, all at the expense of that diamond's ability to reflect light.

Therefore, one can see that the value of a diamond can vary as much as 40% in the cutting alone.