Shell large, solid, depressed, with five to seven whorls ; light brown with a few touches of white transverse to the whorls on the carina; umbilical rib white; nucleus and interior walls of the umbilicus dark brown. Several of the spiral grooves above and below are marked by a darker brown than the rest, and appear as brown lines. Sculpture above, on the nuclear whorls, of closeset sharp longitudinal grooves with the ridges between them rounded and more or less beaded or nodulous, crossed by more or less evident lines of growth, which, however, are not necessarily coincident with the beading where present; the grooves continue, but do not seem to increase in number, while all sculpture disappears from between them, the interspaces being "smooth and flat and only marked by very light lines of growth. The carina is separated from the rest of the Whorl by a squarish shallow gutter, somewhat too broad to be termed a groove, while the base rounds up over the periphery so that the most angular edge of the carina is at the top ; base between Hat and rounded, marked by evanescent (partly brown) grooves and transversely by delicate flexuous slightly raised aggregations of the lines of growth at somewhat regular intervals; these slightly crenate the umbilical rib on its inner edge and perhaps form the. pronounced, slightly backwardly flexed, striae and ridges winch mark the umbilical walls. There is hardly any callus on the body wall at the aperture, which is broken in the specimens at hand ; its form has been made out from the lines of growth ; the suture in the later whorls is closely appressed, the carinal gutter would at first sight he taken for it ; the first two and a half whorls are solidly tilled with translucent shelly matter. Alt. of base, 6.0 mm; of spire, 4.75. mm; Diam. of base, 15.5 mm; of umbilicus, 3.12. mm; Width of aperture, 7.0 mm.

C. brunneum was described by Dall in 1881 as the only species in the genus Fluxina. In 1889 he added a second species, F. discula (probably a Basilissa), and placed the genus in the Solariidae (=Architectonicidae). A specimen of this species was found in a pile of construction sand near Havana, and Aguayo (1949) correctly assigned it to Calliostoma, but he did not realize that his new species, tejedori, was conspecific with F. brunnea. The 2 species remained unquestioned until Merrill (1970a) examined the type of F. brunnea while researching the Atlantic Architectonicidae. He recognized that tejedori was the same as brunnea and synonymized Fluxina with Calliostoma.
This is a distinctive species, resembling in shape C. bigelowi and C. springeri Clench & Turner, but has very little sculpture on the body whorl and a brownish-red umbilicus. The only other species in the Western Atlantic with a colored umbilicus is C. barbouri (q.v.), but the 2 species are completely different in shell shape and sculpture.

From the NW corner of the Great Bahama Bank south to Cuba, Jamaica, and Barbados.
Bathymetric range: From 5-27 m to 1767 m.