The weight of diamonds is measured in "carats" (CARAT). Each carat is equal to 0.2 grams. Each carat is divided into 100 points; for example, a half-carat diamond is actually a 50-point diamond.
The price of a diamond increases according to its weight as a single unit. This means that a one-carat diamond (100 points) will be significantly more expensive than 100 diamonds, each weighing one point.