Speckled grey granite. Unglamorous, unkillable, and correct for anything a truck drives on.
Salt-and-pepper granite is the plain workhorse of exterior stone: a speckled grey-and-black field with no drama at all and mechanical properties that shrug off everything.
It is the standard for step treads, curbing, driveway aprons, and any place a vehicle wheel or a snow shovel will land. A thermal (flamed) finish gives it a rough, permanently non-slip face that lasts as long as the stone.
Nobody chooses it for beauty. People choose it because in twenty years it will look exactly as it does now, which around an entry or a drive is its own kind of good design.
Each of these opens the library filtered to everything suitable for that use, so you can see what Salt & Pepper Granite is competing against.
Post the project and contractors working in your county bid on it — with this stone already specified.