57 stone has an average size of ½ to 1-1/2 inch and is a sound, hard naturally occurring material. 57 stone aggregates may contain, gravel, granites, limestone, dolomite, and sandstone. It is most often used as a base for driveways, walls, pipe bedding, concrete.
Sold by the ton.
The coverage for this product is about 90-100 sq/ft at a 2″ depth per ton.