A common currency among coastal peoples worldwide was shells.
China had cowry shells, the shells were so influential on their culture that the character for cowry shells is used as the symbol for currency. North Chinese had in times of shell shortage used metals such as bronze and gold forged into the shell shape for currency. Besides the metals bone and jade 'shells' were made as well.
In African nations the cowry shell was also the currency of choice. The use of the shell originated on the Western coastal nations and spread east through Muslim traders.
Shells also saw significant use on both sides of the American continent by native tribes. On the east coast, most prominently in what is now New England, native tribes used wampum. Wampum are actually clam shells and legal tender in the Massachusetts Bay Colony. Wampum was carried about in wampum belts, literally belts inlaid with wampum.
On the western American coast tribes used two different types of shells. Californian and Mexican area tribes used Olivella shells. Tribes north of them along the coast up to Alaska used Dentalium shells.