Breccia

Rocks of all types are used for decorative purposes or for inside paving. Breccia is a type of rock composed of large angular fragments that have become cemented together. Unlike the cobbles in conglomerates, which have been rounded by transport, the angular fragments of breccias have been formed in place rather than by erosion and sedimentation. Common in stratigraphic formations, they form in many ways: collapse of cave deposits, igneous activity, diastrophism, and meteorite crater impacts. Nearly all rocks are subject to some natural breakage, but they are considered breccias only when a considerable amount of fine grained cementing material (matrix) is produced during fragmentation.