A common currency among coastal peoples world wide were shells.

China had [cowry shells] (http://www.shells-of-aquarius.com/images/ringtop-cowrie.jpg) started using cowry shells around 1200 BC, the shells became so influential on their monetary system that the character for cowry shell is the same as the one for currency. North Chinese had even used their metals such as bronze and gold to forge them into shells shapes as currency. Besides metal they also made bone and jade shells.

In African nations the cowry shell was also the choice currency. It originated in Western coastal nations and spread eastward through Muslim traders.

Lastly, shells saw significant use on both sides of the American continent by the Native tribes. The East Coast, most prominently in what is now New England, Native tribes used wampum. Wampum are clam shells and were legal tender in the Massachusetts Bay Colony. Wampum was often carried in Wampum belts, literally belts inlaid with wampum.

On the West American Coast tribes used two different types of shells. California and Mexican area tribes used Olivella shells. Tribes in north California and up to Alaska used the Dentalium shells.