Carat: A diamond’s weight is measured in carats.
A diamond’s weight is measured in carats. One carat is equal to 200 milligrams, or 0.2 grams. The weight of smaller diamonds is often expressed as points instead of carats -- there are 100 points in a carat. Another way to look at it is to say that each point equals 0.01, or one-hundredth, of a carat. For example, 0.08 means eight one-hundredths, so a 0.08 carat diamond equals eight points.
NOTE: Don't confuse "carat weight" with "karat," which is the method of determining the purity of gold.