A hard, rounded mass that formed by the precipitation of Inorganic substance that is (1) naturally occurring (but does not have a biologic or man-made origin) and formed by physical (not biological) forces with a (2) defined chemical composition of limited variation, has a (3) distinctive set of of physical properties including being a solid, and has a (4) homogeneous Click on Term to Read More cement within the spaces between sedimentary particles and enclosing a Core of an atom, where nearly the entire mass and all positive charge is concentrated. It consists of protons and neutrons. Click on Term to Read More, such as a shell or fossil. They range in diameter from centimeters to meters. Concretions are found in sedimentary rock or soil and often ovoid or spherical in shape, although irregular shapes do also occur. The word “concretion” is derived from the Latin “con” meaning “together” and “crescere” meaning “to grow”.