Carat

Carat is often confused with size even though it is a measure of weight. The cut of a diamond can make it appear larger or smaller than its actual weight. One carat is the equivalent of 200 milligrams. One carat can be divided into 100 "points". A .75 carat diamond is the same as 75 points or a 3/4 carat diamond. Since larger diamonds are rarer than smaller diamonds, the value rises exponentially with carat weight.