concretion

Noun

concretion (countable and uncountable, plural concretions)

1. The process of aggregating or coalescing into a mass.
2. A solid, hard mass formed by a process of aggregation or coalescence.
3. A rounded mass of a mineral, sometimes found in sedimentary rock or on the ocean floor.
   • Of the three beds, the central one is the most compact, and more like ordinary sandstone: it includes numerous flattened spherical concretions.1844, Charles Darwin, chapter 5, in Geological Observations on South America
4. The action of making something concrete or the result of such an action.
   • "My new statue!" said Kenyon. . . . "It is the concretion of a good deal of thought, emotion, and toil of brain and hand."1860, Nathaniel Hawthorne, chapter 14, in The Marble Faun