Shell small to medium sized (to 69 mm: LACM AE 58-40-72), oval, somewhat arched, little convex. Spire depressed, visible in ventral view. Holes medium sized, oval, hardly elevated, usually 4-7 open. Dorsal surface with highly distinct spiral grooves of variable strength and variable spacing, broad cords sometimes with small bumps, growth lines from barely perceptible to distinct. Coloration usually of dull and dark brick red, but may range form true brick red to dark greenish-brown; some specimens with distinct spiral band. Most specimens with some irregular mottling; regular patterns such as flammae and uniformly colored specimens less common. Columella of medium width. Nacre bright, in red specimens with magenta sheen, in brown specimens pure white. No muscle scar.

The European H. tuberculata does not have as pronounced spiral sculpture if any, and the apex is usually less eccentric.

Type locality: Cape Verde Islands. Range: Canary Islands, Azores