Breccia is a detrital sedimentary rock composed of gravel-sized fragments. Breccia is very similar to conglomerate; however, the pieces that make up breccia are sharp and angular whereas conglomerates have rounded particles. Breccia’s sharp particles indicate that the rock has not traveled very far from its origin so the angles of the particles have not been worn down. This particular specimen is made from the sedimentary rock chert, and is therefore called chert breccia. Department of Earth, Atmospheric, and Planetary Sciences