Boulder-sized clasts are located in some stratified rocks, such as crude corporation and also stone clay. In geology, a boulder is a rock fragment with size above 256 millimetres (10.1 in) in size. While a rock might be tiny adequate to relocate or roll manually, others are very substantial. In common use, a rock is as well huge for a person to move. Smaller sized rocks are normally simply called rocks (American English) or rocks (In British English a rock is bigger than a stone).