Shell rather solid, elongate, ovoid. Whorls 8, the first 1,5 subplanate, the following convex, separated by a more or less distinctly marginate suture; the last whorl more than two-thirds the total length. The surface is shining and appears smooth at first sight, but under a lens the early whorls are seen to be finely punctate, and the following ones very delicately shagreened. There are also, moreover, distinct descending lines on the upper part of the last whorl and over the whole of the preceding whorls. Aperture nearly half the length of the shell, the lip acute and simple. Columella nearly straight, a little twisted, obliquely truncate at the base, the margins joined by a thin callous. Color white, with very wide, zigzag, blackish-brown flammules, which ordinarily tend to predominate, so that the last whorl sometimes seems to be black with some white lightning-stripes; but they are always narrower below the suture, leaving a lighter zone along the upper part of the whorls. The cuticle is golden-yellow. The summit is purple-rose or deep violet, nearly black. Columella and interior of the aperture covered with a bluish enamel, showing the flames by transparence. Length 93, diam. 50, aperture 47x30 mm.

Remarkable for its beautiful coloration. It differs from A. kraussi by the less high last whorl, shorter, more perpendicular and less arcuate columella, non-crenulate suture, or with the erenulation extremely weak, and by the distinct and more angular flames. It is smaller than A. tincta, more oval, less turrited, the columella especially narrower, and the surface finely shagreened, while that of A. tincta is entirely smooth. A. buchneri Mart, also has some resemblance to A. weynsi, but its spire is larger, more conic, and the surface is wholly covered with fine, regular granulation, while A. weynsi is irregularly shagreened and more glossy. The coloration is also quite diverse.