Boulder-sized clasts are discovered in some stratified rocks, such as crude corporation as well as boulder clay. In geology, a stone is a rock piece with size above 256 millimetres (10.1 in) in diameter. While a stone may be little adequate to relocate or roll by hand, others are extremely huge. Alike usage, a stone is as well big for a person to move. Smaller rocks are typically simply called rocks (American English) or stones (In British English a rock is larger than a rock).