The most smooth gravel is river.

Gravel from crushed stone differs in that it is smooth. Where the paths are laid with gravel, it is quite important. However, mountain gravel can have a rough surface. The most smooth gravel is river. In addition, river gravel is cleaner. For landscape design, the smoothness of gravel is a useful property, but for adhesion to the solution in concrete, the smoothness of the aggregate is not its advantage. Better for such a solution, pebbles with corners cling, that is, crushed stone. This is why there is interest in crushing crushes in crushers.