Crushed rock ranges in size from 3/8" to 12+" in diameter. The most common sizes are 3/8" and 3/4" and is an ideal groundcover to surround trees or plants, for pathways, driveways, and more. The larger sizes (1"3", 3"8") are often referred to as "Rubble" and can be used to slow water run off in drainage areas or to separate various areas ...