Stone Dust is sold by the ton.

Stone Dust is a byproduct of the crushing process in which other (such as ¾” and 3/8” driveway stone) comes from.  It is used primarily for a setting layer in setting patio pavers or flagstones in place of concrete sand.  Some other uses for stone dust is in horse barns as a stable surface for horse areas.  It is also used as a filler between large pieces of flagstone. 

1 Ton will cover approximately 100 sf. 2” deep.  If compacting by hand or mechanically, coverages and depth may be affected.