Shell moderately large for genus, cream-colored under thin, pale brown, shiny periostracum. Proto-conch smooth, tip pointed, protoconch diameter 0.35 mm; teleoconch whorls 5; early suture slightly impressed, becoming deeper on later whorls; suture gradually descending on final whorl. Last whorl broadly inflated; aperture markedly oblique, umbilicus narrow. Peritreme nearly complete; inner lip thick, parietal lip reflected, almost blocking umbilicus. Spiral sculpture of fine, microscopic incised lines, about 24 on penultimate whorl, 18 on body whorl; axial sculpture of fine growth lines. Interior iridescent, chiefly lavender. Lateral teeth of radula 7 pairs, overhanging tips long and tapered, tips rounded, both edges finely denticulate. Dimensions: Height 10.1 mm, diameter 12.2 mm (holotype)

This is the only member of Margarites, s.s., in which there are 7 pairs of lateral teeth in the radula. Such similarly proportioned, shallower occurring species as M. helicinus (Phipps, 1774), M. beringensis (E. A. Smith, 1899), and M. albolineatus (E. A. Smith, 1899) lack spiral sculpture and have 6 pairs of lateral teeth in which the tips of the outer laterals are broader than those of M. hickmanae. In size the new species most resembles the offshore M. gigantea (Leche, 1878), but that species has 4 pairs of lateral teeth, a less inflated final whorl, and a darker, dull-surfaced periostracum. Margarites hickmanae is larger than M. argentata (Gould, 1841), which has 5 pairs of lateral teeth. M. pribiloffensis Dall, 1919, is here regarded as a synonym of M. argentata, the holotype having 5 pairs of laterals.)
Remarks: The holotype of M. hickmanae was figured by DALL (1925) under the name M. beringensis (E. A. Smith, 1899), a species described from the Commander Islands (west of the westernmost of the Aleutian Islands). Margarites beringensis differs in having a glossy brown surface and gray early whorls; it is common at low tide in Alaska and British Columbia.

Type locality: 99 m (54 fm) on sand and shell bottom, Petrel Bank (near Semisopochnoi Island, Rat Islands, Aleutian Islands), Bering Sea, Alaska (52°H'N; 179°57'W).