Carat is the unit of weight for the diamond. A carat is further subdivided in 100 points ( 0.01 carat = l point ). One carat is equal to 0.20 grams. Value
per carat increases with carat size, because larger rough diamonds
occur less frequently. In other words, 2 half-carat diamonds taken
together will not cost as much as 1 one-carat diamond, as the
one-carat stone is more rare.