Q. What is the difference between stones and pebbles?

Answer

Pebbles, stones, rocks, and boulders are all different names for the same item, which is rock material. The size is the primary distinction. Boulders are pieces of rock that are more than a foot across or so, while pebbles are bits of rock that are less than 2.5 inches - approximately speaking. Stone is the word that is often used for huge volumes, while rock is basically the generic phrase.