Breccia is a rock composed of broken fragments of minerals or rock cemented
Cementation may refer to:*Cementation , the process of deposition of dissolved mineral components in the interstices of sediments*Cementation , a small deposit of calcium, similar to a cyst...

 together by a fine-grained matrix
Matrix (geology)
The matrix or groundmass of rock is the finer grained mass of material in which larger grains, crystals or clasts are embedded.The matrix of an igneous rock consists of finer grained, often microscopic, crystals in which larger crystals are embedded. This porphyritic texture is indicative of...

, that can be either similar to or different from the composition of the fragments.

The word is a loan from Italian
Italian language
Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...

, and in that language indicates either loose gravel or stone made by cemented gravel. A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic
Tectonics is a field of study within geology concerned generally with the structures within the lithosphere of the Earth and particularly with the forces and movements that have operated in a region to create these structures.Tectonics is concerned with the orogenies and tectonic development of...

 breccia, igneous breccia, impact breccia and hydrothermal
Hydrothermal circulation
Hydrothermal circulation in its most general sense is the circulation of hot water; 'hydros' in the Greek meaning water and 'thermos' meaning heat. Hydrothermal circulation occurs most often in the vicinity of sources of heat within the Earth's crust...

Sedimentary breccias are a type of clastic
Clastic rocks
Clastic rocks are composed of fragments, or clasts, of pre-existing rock. Geologists use the term clastic with reference to sedimentary rocks as well as to particles in sediment transport whether in suspension or as bed load, and in sediment deposits.- Clastic metamorphic and igneous rocks :Clastic...

 sedimentary rock
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....

 which are composed of angular to subangular, randomly oriented clasts of other sedimentary rocks.