William Bramley/The Gods of Eden/21/216/2

In contrast to notes are coins, which functioned somewhat differently. Metals have always been considered valuable, and so pieces of metal were convenient trading tools. Metal pieces were imprinted with various designs, thereby becoming coins, and their metallic purity was guaranteed by the imprinter. Coin values were initially determined by the quantity and purity of the metal contained within the coins. Gold was a rare and popular metal, so coins made from gold were more expensive and had a higher barter value than, for instance, copper coins.