Cobblestone
A cobblestone is a rock that has been asked to lie down in a row and has done so for four hundred years.
Gravel
Gravel is lots of small rocks that agreed to be gravel together, rather than face being a stone alone.
Brick
A brick is a rock that has been taught to stack, and has never forgotten.
Cliff
In 1974 geologists abseiled for eight days to find out what was at the bottom of a cliff. It was the bottom.
Sand
Sand is a very large number of very small rocks, about four of which will follow you home from every beach.
Grey
Grey is the colour between black and white, chosen by rocks and office carpets as the safe option.
Boulder
The size of a boulder is directly proportional to how big it is, a finding that took geologists forty years to confirm.
Mountain
A mountain is a hill that has been promoted, and like most promotions, it went straight to its head, which is now covered in snow.
Pebble
A pebble is a boulder that settled for less, and is mostly found on beaches, in rivers, and inside your shoe.
Rock (rock)
A rock is a piece of rock that is mostly made of rock; analysis of the inside found more rock, which disappointed everyone.