The standard measure for diamond weight is the carat. A carat equals 1/5 of a gram (or 1/142 of an ounce). Each carat is further divided into points, each point representing 1/100 of a carat. While weight may be the least important of the four Cs in determining value, it may be the easiest of the four Cs to gauge accurately and is the most objective.
As diamonds increase in size, their cost tends to increase exponentially. Thus, a one-carat diamond may cost more than twice as much as a one-half-carat stone of equal quality. However, weight does not always enhance the value of a diamond. In fact, when a diamond is improperly cut, added weight may serve only to reduce its brilliance. For these reasons, you should consult with an American Gem Society titleholder regarding the question of weight.
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