Carat Clarity Colour Cut        <<Back   Diamond Carat (ct. or cts.) refers to the weight of the diamond. One carat is equal to 1/5 of a gram. Hence a 5.00 carat gemstone would weigh exactly 1.00 gram. A carat is further subdivided into 100 points ( 0.01 carat = l point ). Since larger stones are more rare, the value per carat increases with carat size. Thus, a two carat diamond will cost more than two one carat diamonds, assuming that all other parameters are constant.