Shell money was once commonly used in many parts of the world. Shell money usually consisted either of whole sea shells or pieces of them, which were often worked into beads or were otherwise artificially shaped. The use of shells in trade began as direct commodity exchange, the shells having value as body ornamentation.
Some form of shell money appears to have been found on almost every continent: America, Asia, Africa and Australia. The shell most widely used worldwide as currency was the shell of Cypraea moneta, the money cowry. This species is most abundant in the Indian Ocean, and was collected in the Maldive Islands, in Sri Lanka, along the Malabar coast, in Borneo and on other East Indian islands, and in various parts of the African coast from Ras Hafun to Mozambique.
Cowry shell money was important at one time or another in the trade networks of Africa, South Asia, and East Asia.
The shell most valued by the Native American tribes of the Pacific Coast from Alaska to northwest California was Dentalium shell, a species of long narrow marine shelled mollusk, a tusk shell or scaphopod. The tusk shell is naturally open at both ends, and can easily be strung on a thread. This shell money was valued by its length rather than the exact number of shells; the “ligua”, the highest denomination in their currency, was a length of about 6 inches.
Farther south, in central California and southern California, the shell of the olive snail Olivella biplicata was used to make beads for at least 9,000 years. The small numbers recovered in older archaeological site components suggest that they were initially used as ornamentation, rather than as money. Beginning shortly before 1,000 years ago, Chumash specialists on the islands of California’s Santa Barbara Channel began chipping beads from olive shells in such quantities that they left meter-deep piles of manufacturing residue in their wake; the resulting circular beads were used as money throughout the area that is now southern California. Starting at about AD 1500, and continuing into the late nineteenth century, the Coast Miwok, Ohlone, Patwin, Pomo, and Wappo peoples of central California used the marine bivalve Saxidomus sp. to make shell money.
On the east coast of North America, the members of the Iroquois Confederacy and Algonquian tribes, such as the Shinnecock tribe, ground beads called wampum, which were cut from the purple part of the shell of the marine bivalve Mercenaria mercenaria, more commonly known as the hard clam or quahog. White beads were cut from the white part of the quahog or whelk shells. Iroquois peoples wove these shells in belts.