Carat weight has a strong influence on a diamond’s price. Larger diamonds are considerably more valuable because they are far less common in nature compared to smaller stones. For this reason, diamond pricing does not increase in a straight line — a single one-carat diamond will typically cost more than two half-carat diamonds of the same cut, color, and clarity.

The effect of carat weight on pricing becomes especially noticeable at what the industry often calls “popular weight milestones.” At specific marks such as 0.50 carat, 0.75 carat, and 1.00 carat, the price per carat can rise sharply. These weights are highly sought after, which increases demand and, consequently, pricing.

For example, a diamond weighing 0.97 carats and another weighing 1.03 carats (with identical cut, color, and clarity) may look almost identical to the naked eye. However, because the second diamond crosses the one-carat milestone, the difference in cost can be substantial.