gravel

easy to find
where: see uses (often places with cars and further from the city)
typical size range 1/4”- 4” (leans toward the former)

sold in bulk
found in groups

even more dependent on existing in multitude than river rock
you couldn’t pick up a single tiny jagged rock and claim to be holding gravel, well you could but colloquially speaking it’d be a pebble
after all gravel is just pretty much just rougher pebbles
well more accurately broken/crushed stone... 
at least that’s how I’m delinating the two 
(how it was eroded/its current shape/its proximity to others)

uses:
base material
drainage
weed supression
driveways
parking lots
unimproved roadways


gravel being used as a weed supressor (in conjunction with plastic sheeting)