From The Food Encyclopedia by Jacques Rolland and Carol Sherman
Any of a large group of bivalve mollusks found in salty coastal waters around the world. New England prides itself on its quahogs, Venus mercenaria, which are also known as hard-shell clams; cherrystones when they're at middle growth; and littlenecks when very young. Littlenecks and cherrystones are eaten on the half shell, but when older and larger, they go into chowders. One edge of the quahog shell is usually deep purple, and there are sometimes splotches of purple elsewhere. The Lenape, Powhatan and Renápe Indians used the purple parts to make bead money, or wampum. Purple wampum was worth twice the value of white, which was made from conch shells. See also Pacific littleneck clam, razor clam.
