This is the largest American scallop, usually measuring 5 to 6 inches, up to 8 inches in diameter. It is found in deeper waters of the continental shelf. The valves are flattened, upper shell slightly concave, ears or wings small, usually equal and symmetrical, color of upper valve light brown; surface covered with numerous fine threadlike ribs radiating from beak and crossed with readily visible concentric growth lines; lower valve white and with much weaker radiating ribs; inner lining of both shells is smooth, white and iridescent and has a conspicuous central muscle scar. Upper valve (shell) is reddish or purplish brown. This mollusk’s range extends from New Jersey to Labrador. It is especially abundant off the coast of Maine in 10 to 100 fathoms. This commercially important species is the "sea scallop" found in local markets. The edible portion is the large, powerful adductor muscle that this bivalves uses to open and close it's valves (shells). When threatened by predators it can clap these rapidly and produce lift, thereby swimming out of harms way.

Live specimens have a number of blue eyes that rim the periphery of the mantle and can be seens as the scallop relaxes.