1700
Due to its scarcity, copper, the "red" metal, was associated with kings, leadership and wealth, all important factors in its use as currency. In parts of west and central Africa, copper ingots were a widely used form of currency. An ingot is a mass of metal cast into a bar, arch, X or H shape. Ingots were used as stored wealth that could be easily transported and used as a unit of currency. They are cast in a range of sizes, and are often melted down and re-cast into different shapes.