It has 21-25 radial spines that are slightly bent backwards, thickened at the base, glassy white with a brown tip, and measure 3-6 mm in length, except for 2 or 3 bristle-like spines that can reach up to 2 cm.

Additionally, there are 2 brownish-black central spines that turn grey with age, one of which is erect and darker, measuring around 15-20 mm long.

The flowers of Rapicactus zaragosae are slender and funnel-shaped, ranging in color from pale yellow to violet, with a darker mid-vein.

[3] Plants are found growing on gypsum hills in the municipalities of Zaragosa and South of Aramberri in Nuevo Leon, Mexico at elevations of 1200-1700 meters.

The plants are found growing with Thelocactus conothelos subsp.