Rocks that are Rounded, Subrounded and Subangular

Rock Fragment : Boulder
Size of Fragment: More than 256 mm
Aggregate: Boulder, gravel or conglomerate

Rock Fragment: Cobble
Size of Fragment: 64 to 256 mm
Aggregate: Cobble, gravel and cobble conglomerate

Rock Fragment: Pebble
Size of Fragment: 4 to 64 mm
Aggregate: Pebble conglomerate and pebble gravel

Rock Fragment: Granule
Size of Fragment: 2 to 4 mm
Aggregate: Granule sand

Rock Fragment: Sand
Size of Fragment: 1/6 mm to 2 mm
Aggregate: Sand and sandstone

Rock Fragment: Clay
Size of Fragment: Less then 1/256 mm
Aggregate: Clay and shale