Limestone formations are usually clearly layered. Pure rock is light-colored. ... Dark gray spots are chert nodules and the boulders on the coast are also made of this rock type. Limy mud is often purely chemical precipitate.

Do limestone rocks have layers?

Oolitic Limestone

Oolites (or ooliths) are small, sand-size clasts of calcium carbonate with a spherical to ovate shape. They form by the concentric accumulation of calcium carbonate layers around a nucleus that might be a sand grain, a shell fragment, a coral fragment, or a particle of fecal debris.

Why does limestone form in layers?

Sedimentation – A Process of Rock Formation

In sedimentation, one layer of organic, non-organic, and other substances laid on another in stacks. The buried layers getting compressed due to increased weights of top layers. So, the process is known as Diagenesis turns sediment to rock.