One of the easiest terms to understand is a diamond’s carat. Simply put, carat is the weight of a gemstone or diamond on a gem scale.

The 4Cs – Diamond Carat Weight

Carat is often the first thing to come to mind when thinking about a diamond’s size. Size and carat weight are closely related but there are other factors in a diamond’s appearance. Cut and shape also play a role in whether the diamond appears visually larger or smaller than its actual carat weight.


“Carat” comes from the word “carob”—a small tree in the Middle East with edible pods. Prior to the modern measurement system, gemstones and diamonds were weighed using the small, lightweight seeds from carob pods to counterbalance the scales. Since then, one carat has been standardized and is now equal to 200 mg.

The 4Cs – Carat vs. Karat


Both are used to assess the value of jewelry. Carat is the weight of a diamond. Karat, on the other hand, measures the purity of gold.