A mechanical crusher is used to break rock - part of the process of producing sized aggregate for asphalt production and comes in two main types of either hard or soft stone.

rock fragments and pebbles

An aggregate made from crushed rock, as distinct from crushed gravel.

Natural stone that has been mechanically crushed and sorted to produce sharp edged stone of uniform size. This material is typically used for walkways, paths, driveways, parking areas, and to highlight other landscape features such as Centerpiece boulders.