Carat is a unit of measurement that is of the utmost importance in jewellery making. On the one hand, carat, which is abbreviated to kt. or C. or ct., denotes the content of pure gold in an alloy, and on the other hand, the metric carat is used to quantify the mass of gemstones. The word carat was borrowed from the French "le carat". However, the word has its origin in Greek, where "kerátion" is the diminutive of horn. The horns relevant to the carat are the legumes of the carob tree, which used to be used as units of measurement in weighing because they were said to always have the same size and weight. A carat was the specific weight of a dried seed of this fruit. Today, the metric carat is equivalent to 200mg. Carat is used as an indication of the fineness of gold, where one carat of gold is 1/24 of the total weight of gold. 24 karat gold is at least theoretically 99.9% pure gold. Commonly used in jewellery making are 8 carat, 9 carat, 14 carat and 18 carat gold. The carat is the legal unit of measurement used to determine the mass of gemstones. One metric carat is 0.2g, which corresponds to 2*10-4 kg.
