Shell is large, inflated, laterally compressed, elongate to rectangular with a large dorsal wing; anterior end sharply rounded; posterior end broadly rounded. Umbo is flattened and only slightly raised above hinge line. Epidermis is brown to greenish-brown, becomes darker with age; juveniles often with faint green rays, later fading. Inside shell beak cavity is shallow; pseudocardinal teeth relatively thin, small and rough; lateral teeth high and moderately long, bladelike and straight to slightly curved; nacre (lining) purple to pinkish-purple.
Similar species: White heelsplitter is compressed and rounded with a white nacre. Pink papershell has a thinner shell, is less inflated, is not rounded posteriorly and has reduced teeth. Bluefer is more inflated with a deeper beak cavity and a squared posterior end.