The word is a loan from Italian, and in that language indicates both loose gravel and stone made by cemented gravel. 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.
Types of Breccias
Sedimentary breccias are a type of clastic sedimentary rock which are composed of angular to subangular, randomly oriented clasts of other sedimentary rocks. Collapse breccias form where there has been a collapse of rock, typically in a karst landscape; collapse breccias form blankets in highly weathered regolith due to the removal of rock components by dissolution. Tectonic breccias form where two tectonic plates create a crumbling of the interface, by their relative movements. Fault breccias result from the grinding action of two fault blocks as they slide past each other; subsequent cementation of these broken fragments may occur by means of mineral matter introduced by groundwater. Intrusive rocks can become brecciated in appearance by multiple stages of intrusion, especially if fresh magma is intruded into partly consolidated or solidified magma.