A complex type of rock made of shattered, crushed, and (in some cases) once-melted fragments of rock, all cemented together by a finer-grained material (the matrix). It is a common result of impact processes on planetary surfaces. A genomict is a breccia in which the components originated in distinct but genetically related rocks. A monomict is a breccia in which all the components originated in the same type of rock. A polymict is a breccia in which the components originated in two or more rocks of differing compositions.
Subjects: Astronomy and Astrophysics.