The term 'diamond measure' is often used to refer to the unit of measurement for diamonds, which is the CARAT (5 letters). A CARAT is a unit of mass equal to 200 milligrams and is used to measure the weight of diamonds. It is also used to measure the weight of other gemstones, such as rubies and sapphires. The CARAT is divided into 100 points, so a diamond that weighs 0.25 carats would be referred to as a 25-point diamond.