Caryocorbula dietziana is a small (reaching 15 mm, or 0.6-inch) bivalve of a family notorious for their difficult and confusing taxonomy, the Corbulidae, also known as Basket Clams. Its shell has the posterior ridge typical of the family. Like in most other corbulid species, the right valve is larger than the left one, and this difference is accentuated in this species as the clam grows older, which renders a gnarly aspect to those shells. The Dietz Rose Corbula may be rose, whitish, or cream-colored, sometimes showing flecks of gray or light-brown. The inner surfaces of the valves may be tinged brown near the margins. The species is found from North Carolina through both coasts of Florida and parts of the northern Caribbean region.
