I always wonder,,,, who the hell thought these up???? It certainly wasn't a blue collar worker at the quarry or on the construction site. Some overpaid white collar pencil pusher that wanted to know something you do not.
For example, in all of your excellent descriptions of the various gravels above, none of the names, not one, have any implication as to the size of the gravel. None.
Very amusing to me. But then I'm the blue collar grader operator trying to order a load of gravel that makes sense for the project at hand.