The carat is a unit of mass, which is used for gemstones and pearls. One Carat is equal to 0.2g. The current definition was adopted in 1907 at the Fourth General Conference on Weights and Measures. Officially, the carat can be divided into 100 pointsof 2 milligrams each.
- American Association for the Advancement of Science (1908). Science. American Association for the Advancement of Science. p. 144. Retrieved 30 June 2012.