Carat

A carat is a unit of weight equal to one-fifth of a gram (0.20g), used to measure most gemstones — especially diamonds. It should not be confused with karat, which refers to the purity of gold.

For smaller stones, carat weight is often expressed in points, where one point equals 0.01 carats. For example, a 25-point diamond is 0.25 carats.

When a diamond is cut from rough into a finished stone, more than half of its original carat weight is often lost. This transformation — known as the make of the diamond — determines the final shape, proportions, and facet angles. How that weight is distributed in relation to the finished size plays a key role in evaluating both beauty and value.

Importantly, carat weight does not increase proportionally to face-up size. For instance, a 1-carat round diamond typically has a crown diameter of 6.4–6.5mm, while a 3-carat round has a diameter around 9mm — not triple the surface area. Understanding this helps distinguish weight from visual presence.