Globular cactus, seldom exceeding 5 cm in diameter and rather less in height, with 9 to 11 rounded ribs. These are in turn crossed by numerous horizontal furrows. Between these true ribs are small secondary ribs, reaching about halfway up the plant body. The colour of the younger growth is a rather pale yellowish green, merging to grey-green on the lower, older growth. The centre of the cactus contains a lot of white wool. Once the plant body has reached full size it slowly offsets, and small clumps are commonly found. It does not develop a large storage root.
Aztekium is a small plant (around 20 mm wide), with 9 to 11 ribs, which typically have transverse wrinkles. Its color varies from pale green to grayish-green. The center of the cactus contains a lot of white wool. Flowers are small (less than 10 mm wide), with white petals and pinkish sepals. The plants bear small pinkish berry-like fruits. A. hintonii is larger, to 10 cm in diameter, 10 to 18 grooved ribs, flowers magenta to 3 cm. It grows only on gypsum.