Graywacke

Definition

Graywacke is a type of sedimentary rock that is characterized by its dark gray color and coarse-grained texture. It is composed of a mixture of different-sized rock fragments, such as sand, silt, and clay, which are held together by a fine-grained matrix.

Related terms

Conglomerate: A type of sedimentary rock similar to graywacke but with rounded rock fragments instead of angular ones.

Sandstone:

Another type of sedimentary rock composed mainly of sand-sized grains.

Shale: A fine-grained sedimentary rock formed from compacted mud or clay particles.