gravel = plural of gravaEn geology and in construction, it is called gravel to rocks of size between 2 and 64 mm. They can be produced by the human being, in which case it is often called «stones» or «lime», or the result of natural processes. In this case, moreover, usual wear and tear caused by movement in the riverbeds have generated rounded forms, in which case it is known as Boulder. There are also cases of natural gravel which are pebbles.
