Convert Stone (US) to Ton (assay) (US)

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 ton assay originated in the United States as a unit of mass for assaying precious metals. It was defined as 29.16666667 kilograms or approximately 64.58333333 pounds. The term "ton assay" comes from the practice of assaying, which is the process of determining the content of precious metals in ore samples. The ton assay is used in the United States for this purpose.