Diamond weight is measured in carats (compared to "karats," a measure of a metal's
purity). A carat equals about 1/5 of a gram, and is divided into 100 parts, or "points."
A 150-point diamond, therefore, would weigh 1.5 carats.

While carat weight is the most frequently cited of the "four C's," it is by no means the
most indicative of its worth. A diamond with superior clarity, cut or color can be worth
much more than a larger stone.