Term used to describe the fineness/purity of
gold. A karat is one part out of 24 (this comes from ancient
coins: At the time of
Constantine, 24 kerations were equal to a golden solidus), so 24-Karat gold is completely
pure. However, gold is so
soft that 24-karat is not all that practical for
jewelry, so 14-karat gold (14 parts gold, 10 parts some other
metal) is perhaps the most common type used for jewelry.
Occasionally spelled "carat," but a carat is a unit used for the weight of gemstones, so the "k" spelling is much less confusing.