CARAT WEIGHT: Although commonly thought to refer to the actual size of a diamond, a carat is actually a standard unit of measure that defines the actual weight of a diamond. One carat is equivalent to 200 milligrams. Carat sizes are also expressed as "points" with a one carat diamond equaling 100 points, a three-quarter carat diamond being 75 points and a one-half carat diamond being 50 points, and so on.

Larger diamonds are much more rare than smaller ones. In fact, hundreds of tons of rock and ore must be processed to uncover a single one-carat gem quality diamond. And less than one percent of all women will ever own a one-carat or larger diamond.

Since a carat measures weight instead of size, two diamonds of the same carat weight may appear to be different sizes depending on how the diamond is cut. Some diamonds will have extra weight on the bottom part - or pavilion - of the stone, and therefore appear smaller. Because a Hearts On Fire diamond is perfectly cut, it will appear larger than many diamonds of a heavier carat weight.