Shell small to medium size for genus; average adult size 104 mm SL (n = 5), maximum 105.9 mm SL. Protoconch) of 2.5-3 whorls; first 1.5-2 whorls smooth, inflated; final whorl usually of smaller diameter, bearing thin, arcuate axial ribs of varying density and number, sometimes terminating in varix. Teleoconch of approximately nine well inflated whorls. Early teleoconch whorls bear six major spiral cords that form thickened lobes in crossing axial ribs, giving characteristic gemmate appearance. Cords notably thicker between periphery and anterior margin of whorl; postcriormost cord least developed. Minor cords in interspaces of early majors become more prominent in later whorls. Axial sculpture of thick, lightly packed ribs; spaces between ribs bear numerous coarse and occasionally lamellate axial striae that persist over spiral cords. Six original major cords persist to body whorl but are accompanied by increasingly prominent minors, with two or three minors between each major on body whorl, sometimes shouldering a major on either side. Suture adpressed, with broad and slightly undulating subsutural band that bears fine spiral lirae.
Neck of medium length for genus, broad at posterior end. gently tapering with only slight recurvalure. Well spaced spiral cords on outer surface, steepening in angle and becoming less prominent towards distal end, with only faint minors in between; 22-26 major cords between suture and tip of neck at termination of growth. Spiral cords occasionally almost absent from distal third of neck. Aperture leaf-shaped, interior white, glossy and porcellaneous. Labral wall bears smooth spiral lirae. often paired, that correspond in position to troughs between cords on outer surface; lirae terminate slightly before lip in adults. Adult lip thin, sharp but finished; margin smooth overall, slightly indented at termini of major spiral cords, but with no dentition. Parietal wall of aperture glossy; thin porcellaneous layer overlays surface sculpture but spiral cords still clearly visible. Parietal wall resorbed in juveniles, smooth in adults with slightly detached margin that persists until roughly mid-point of canal. Canal straight or slightly recurved, parallel-sided or slightly flaring in distal third; outer margin thin, sharp, columellar margin glossy and slightly resorbed in distal half.
Shell pale cream-white overall; protoconch and primary whorls occasionally mid- to pale brown. Most shells bear characteristic dark brown axial stripes in troughs between ribs, with occasional brown staining of entire upper teleoconch. Stripes present in all material examined, but variable in strength; very pale in some examples and present only on early whorls in others. Spiral cords on body whorl normally of darker color in interstices of axial ribs. Distal part of neck stained mid-brown in some adult specimens, with paler growth periods giving axially striped appearance. Periostracum thin, pale brown, translucent; of lamellar construction with thin, sharp regularly spaced thorns arising both on crowns and in troughs of spiral cords.
Operculum typical of genus; thin, chitinous; pale brown, with nucleus at anterior end. Animal unknown.

Variation: certain specimens of E emmae have finer sculpture on the first three teleoconch whorls, that then reverts to typical. Interestingly, two specimens examined that have this primary whorl morphology also feature a varix at the termination of the protoconch. In some specimens two or three spiral cords below the periphery on the body whorl are somewhat more prominent than the others.
Two other named Fusinus species from Taiwan and the East China Sea off China are of similar size and appearance to F. emmae. From F. diandraensis, E emmae may be distinguished principally by the features of its early whorls, namely (1) the more pronounced and numerous axial ribs; (2) the positioning of major spiral cords at and below the periphery but not above it, and (3) the formation of lobes in the spiral cords where they cross the axials. In addition, E emmae bears distinct color bands between the axial ribs at least in the earliest growth stage, and usually over most of the teleoconch. It may also have a brown spiral band on the body whorl and/or brown staining at the distal end of the neck. The same set of characters serves to distinguish F emmae from E flavicomus. The latter is a poorly-known species of which very few confirmed examples exist, but the holotype and the first paratype both bear two dominant spiral cords on the early whorls that form one or two rows of inflated nodes on the angular periphery that persist onto the body whorl.
In common with many other species in the genus, Fusinus emmae shows considerable variation in the expression of its shell characters. In particular, specimens from the Taiwan Strait have a more angular whorl profile, with a dominant spiral cord at the periphery and a consistently broader canal. The angular profile suggests an affinity with F. diandraensis but the protoconch and primary whorl sculpture both firmly indicate E emmae. Members of this subset also resemble certain variant specimens of E perplexus from the Japan Sea, from which they differ by their stronger, rounded and less numerous spiral cords on the early whorls, their broader neck and canal, and their more prominent and less numerous axial ribs. The Taiwan Strait might represent an impediment to northward distribution of larvae, as its flow reverses direction from south-north in the winter to north-south in the summer (Chernavin & Gorshkov, 1993: pl. 280).
From the typical form of F perplexus, all forms of E emmae differ by their dominant anterior spiral cords with rounded lobes on the early whorls, their longer and more slender neck and their color pattern.
With its strong axial ribs F. emmae might at first glance be mistaken for Fusinus forceps, but that species has characteristic sharp spiral cords that are greater in number than those of E emmae, cross the axial ribs without forming lobes and persist undiminished onto the body whorl; it also has more deeply indented sutures, especially in the early whorls, and lacks any color pattern. Finally, E emmae can be distinguished from the sympatric E salisburyi by its far smaller adult size, its lack of a dominant peripheral spiral cord, its shorter and less recurved neck, and the absence of the latter's distinctive detached anterior parietal aperture margin.

The outer continental shelf of the East China Sea off mainland China, and the Taiwan Strait. Depths given by the collectors fall mainly in a range from 140 to 160 m, but several specimens, including the holotype, are said to have come from between 350 and 380 m. Shell attachments include barnacles, corals, and hard bryozoans. The species is apparently confined to sand and gravel bottoms.