volcanic breccia

Volcanic breccia is a type of pyroclastic igneous rock, meaning it is formed from volcanic activity. It is characterized by large, coarse fragments of rock that are ejected during explosive volcanic eruptions. These fragments are typically angular or subangular and can vary in size and shape.12

Breccia differs from conglomerate in that its clasts (fragments) are angular or subangular, whereas conglomerate clasts are rounded. Volcanic breccias can be composed of fragments of a single rock type or multiple types, and the spaces between these fragments may be filled with cementing material like carbonate, silica, or silt. Some geologists classify these volcanic fragments as bombs, blocks, or breccia, depending on their size and whether they were ejected in a molten or solid state.321