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.