Also known as “The Northern Quahog” or “Hard Clam,” this marine bivalve is found along the eastern seaboard of the United States from Maine to Florida, and is especially common from Massachusetts to New Jersey
Its name is pronounced KO-hog, not “kwag” or “KWA-hog”, and derives from the Narragansett Indians’ name for the clam, "poquauhock.” The interior lip of the clam’s shell is commonly colored light to royal purple to dark purple in stark contrast to the remainder of the mostly-white shell. This segment of the shell was ground into purple beads by Native Americans living along the eastern seaboard of the United States to form “wampum,” an important item of barter among Native Americans. Hence this species of bivalve carries the scientific name of Mercenaria mercenaria, derived from the Latin word for “money”. (Older references may cite this bivalve as Venus mercenaria, but it was reassigned by biologists.)
The Quahog sometimes produces concretions of shell material which range in shape from flattened disks (aptly described as “shaped like an M&M candy”) to spheres, and in color from white to pale purple to a deep purple-black. These concretions lack the lustrous nacreous layers that are characteristic of gem pearls derived from oysters and are composed of layers of aragonite crystals interspersed with organic material.