A coarse-grained sedimentary rock in which large, rounded sediments can be seen is called conglomerate. Conglomerates consist of a variety of rock fragments that have been transported, rounded, and deposited in a sedimentary environment. The fragments in conglomerates can range in size from small pebbles to large boulders. The most common type of conglomerate is composed of rounded pebbles and cobbles of quartz and feldspar, but conglomerates can also contain a variety of other rock types, including limestone, sandstone, and igneous rocks. Conglomerates are typically formed in high-energy environments, such as rivers, streams, and beaches.