1 carat can be divided into 100 pieces, which can be calculated as a relatively small gem. Because the density of diamonds is basically the same, the heavier the diamond, the bigger the volume. The bigger the diamond, the rarer it is, and the higher the value per carat.

The current metric carat unit, that is, 1 carat equals 200mg, was adopted from 1907. Before that, one carat was equal to 205 mg, or 0.205 g.