Carat
Refers
to the weight of a diamond.
Of the 4Cs, carat weight is the easiest to measure and understand. Carat is often confused with size, even though it is actually a measure of weight. One carat equals one-fifth of one gram and is divided into 100 points. So, when you discuss a ¾ carat stone, you could say it weighs .75 carat or 75 points.
A 1-carat diamond costs exactly twice the price of a half-carat diamond, right? Wrong. Since larger diamonds are found less frequently in nature—which places them at the rarest level of the Diamond Quality Pyramid—a 1-carat diamond will cost more than twice a ½-carat diamond (assuming color, clarity and cut remain constant).
Cut and mounting can make a diamond appear larger (or smaller) than its actual weight.
To recover a single,
gem-quality diamond, over 250 tons of ore must be processed. Of these
diamonds, only one in 1,800 will weigh a carat or more. The scarcity of
diamonds creates part of their value; the staggering rarity of large diamonds
dramatically increases their value. Thus, a two-carat diamond will be
more than double the price of a one-carat diamond.