Consist of more than 30% angular fragments in a matrix (groundmass) of sand and clay. The fragments may be derived from sedimentary or metamorphic rocks.
Breccia (Italian: breach) is a rock composed of angular fragments of rocks or minerals in a matrix, that is a cementing material, that may be similar or different in composition to the fragments.
A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic breccia, igneous breccia, impact breccia and hydrothermal breccia.
