concretion

noun4

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
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