Carat is a measure of a diamond’s weight. Essentially, one carat weighs 200 milligrams or one fifth of a gram. However, in reality relatively few diamonds weigh exactly one or two carats. In order to provide an accurate weight for all diamonds, carats are therefore divided into hundredths. As such, a half-carat diamond can also be referred to as a 0.50ct or 50 point stone.

Carat weight is not the only factor affecting the price of a diamond and smaller diamonds with a superior cut, clarity and color gradings can be far more valuable than larger ones of inferior quality. Also, because they are produced naturally, larger stones are much rarer than small ones. Indeed, if all other diamond characteristics are the same, the price of a one carat diamond will be considerably more than double that of one weighing half a carat.

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  • Make an informed choice when selecting a quality diamond. Move the arrow to understand the relationship between carat weight and the physical proportions of a round brilliant diamond.

    The diamond scale (left) is correct on monitors with screen resolution of 94 pixels per inch. Also, all diamonds sold by Hearts of London are independently weighed, graded and certified by totally impartial gemological laboratories

Significant savings can be made when selecting a diamond that weighs slightly less than one or half of one carat. The difference in size, for example, for a 0.40 or 0.95 carat diamond for instance will be very slight but the price will often be far lower.

Our master jewellers and trained gemmologists can help you select a cut and setting that will present any diamond in the most attractive manner. Smaller diamonds can also be set to help them appear larger than they actually are.