rock, stone - material consisting of the aggregate of minerals like those making up the Earth's crust; "that mountain is solid rock"; "stone is abundant in New England and there are many quarries"

ballast - coarse gravel laid to form a bed for streets and railroads

bank gravel, pit run, pit-run gravel - gravel as found in natural deposits

shingle - coarse beach gravel of small water-worn stones and pebbles (or a stretch of shore covered with such gravel)