Hard Clam, Quahog, Northern Quahog, Round Clam
Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Veneridae, Genus: Mercenaria, Species: Mercenaria mercenaria · Veneridae (Venus Clam family) · Bivalve (single valve interior visible), sub-circular to ovate clam shell
Species
Mercenaria mercenaria (High confidence)
Shell Type
Bivalve (single valve interior visible), sub-circular to ovate clam shell
Family
Veneridae (Venus Clam family)
Size
Estimated 2 to 2.5 inches in diameter, representing an average adult size. Full growth ranges from 1.5 to 5 inches.
Color & Pattern
Interior shows a pale off-white to grayish base with distinctive dark purplish-blue staining near the margins, characteristic of quahog shells. Exterior concentric growth rings are faintly visible through the interior shading.
Rarity
Very Common
Habitat
Marine shallow subtidal and intertidal zones, preferring muddy, sandy, or gravelly substrates in bays, estuaries, and protected coastal waters.
Geographic Range
Native to the western Atlantic Ocean from the Gulf of St. Lawrence in Canada down to Florida, and introduced into parts of the US Pacific coast and Europe.
Description
A single interior valve of a classic Northern Quahog shell displaying a rounded, thick structure with visible dark purple interior staining near the margin and hinge area. Concentric growth lines are evident, and the inner shell surface shows moderate weathering.
Key Features
Thick heavy shell, dark purple patches on the interior margin (used historically for wampum), distinct pallial sinus, and prominent cardinal teeth along the hinge area.
Collector Value
Low monetary value ($1 - $5 for beach finds), though highly appreciated for craft use, history, and educational collections.
Condition Notes
Fair condition. Single detached valve, somewhat beach-worn with edge erosion and minor chips along the rim, but retains characteristic purple interior pigmentation.
Interesting Facts
Indigenous Native Americans of the Atlantic coast carved beads from the purple portions of Quahog shells to make 'wampum', which served as sacred ceremonial items and trade currency.
Ecological Role
Important suspension feeder that filters plankton and detritus from seawater, aiding water quality; serves as prey for sea stars, whelks, crabs, and shorebirds.
Similar Species
Southern Quahog (Mercenaria campechiensis), which generally lacks the deep purple interior staining and has coarser concentric ridges.
Beach Finding Tips
Look along sandy or muddy Atlantic beaches, estuarine shorelines, and near clam flats, especially after strong low tides or storm surges.