Convert Stone (US) to Carat

The stone as a unit of mass has roots dating back to ancient times, where it was used in various cultures for weighing goods, with the weight of a stone varying by country and commodity. In the UK, the stone was historically used to measure items like wool, and the weight of the stone varied (ranging from 5 to 30 pounds) based on the goods being measured. The U.S. adopted a 14-pound stone in the 19th century, primarily as a way to measure body weight, though it is now largely replaced by the pound for more precise measurements. The 14-pound stone is still used informally in some areas, especially in the context of body weight.

The carat originated from the use of the carob seed (from the Ceratonia siliqua tree) as a reference for weight in ancient times. These seeds were used because of their relatively consistent weight, and they were widely available across regions. The term "carat" comes from the Greek word "keration", which means "little horn," referring to the carob seed. Over time, the carat became standardized, and in 1907, the International Union of Pure and Applied Chemistry (IUPAC) defined the carat as 200 milligrams, ensuring consistency in the measurement of gemstones worldwide.