The Diamond's Carat

Diamonds are weighed to a thousandth (0.001) of a carat and then rounded to the nearest hundredth, or point. Over a carat, diamond weights are usually expressed in carats and decimals. A 1.03 ct. stone, for example, would be described as "one point oh three carats," or "one oh three." A diamond that weighs 0.83 ct. is said to weigh "eighty-three points," or an "eighty-three pointer." Some weights are considered "magic sizes" – half carat, three-quarter carat, carat. Visually, there’s little difference between a 0.99 ct. diamond and one that weighs a full carat. But the price differences between the two can be significant.