Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically sorted fragments of the shells of either molluscs, trilobites, brachiopods, or other invertebrates. For a sediment to be considered to be a coquina, the average size of the particles composing it should be 2 mm or greater in size. Coquina can vary in hardness from poorly to moderately-cemented. The term 'coquina' is derived from the Spanish word for cockleshells or shellfish. Incompletely consolidated and poorly cemented coquinas are considered grainstones in the Dunham classification system for carbonate sedimentary rocks.
Contributions by 18.104.22.168, Vsmith, and Wilson44691.