The title refers to the amount of gold present in the alloy that composes the jewel, measured in thousandths per gram. The carat is a unit of measurement that corresponds to 41.6 thousandths of a gram of gold in the alloy. These are the commonly used titles for making jewelry:
- 8 carats = 333 thousandths of a gram
- 12 carats = 500 thousandths of a gram
- 14 carats = 585 thousandths of a gram
- 18 carats = 750 thousandths of a gram
- 22 carats = 916 thousandths of a gram
- 24 carats = 999 thousandths of a gram