Carat (Ct) is the unit of mass (weight) of gemstones, and the weight of diamonds (diamond rings) is also expressed in carats, such as 1 carat diamond ring, 2-carat diamond ring and 10-carat diamond ring which are common in the market. Converted from the usual weight unit, 1 carat is equal to 0.2 g or 200 mg. There are even smaller diamond rings, not measured in carats, but in minutes. One carat is equal to 100 cent, and vice versa. The two can be converted to each other, such as 50 cents =0.5 carat and 0.8 carat =80 cents. Generally speaking, the bigger the weight, the bigger the diamond ring.