concretion

noun

1. (countable, uncountable)The process of aggregating or coalescing into a mass.
2. (countable, uncountable)A solid, hard mass formed by a process of aggregation or coalescence.
3. (countable, uncountable)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.”

4. (countable, uncountable)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."”