Breccia is a rock composed of angular fragments. It is produced by sedimentary, magmatic, or tectonic processes. A sedimentary breccia is a coarse-grained (particle size >2 mm) rock composed of angular rock fragments held together by cement or dispersed in a fine-grained solidified matrix. It originates as a result of sedimentary processes such as talus accumulation (sedimentary breccia), disturbance during sedimentation (intraclastic breccia), or collapse of rocky surfaces such as the roof of a cave (collapse breccia). Magmatic breccia results from explosive eruptions (pyroclastic breccia), hydrovolcanic fragmentation in diatremes (funnel-shaped pipes), or mechanical fragmentation in intrusive settings. Tectonic processes such as frictional slip along a fault produce fault breccia. Breccia containing angular clasts and fine-grained matrix produced by meteoritic impact is a common rock on planetary surfaces. The anorthositebrecciaof the lunar highlands...