Arlington Heights, Massachusetts, USA where I live, like Boulder Colorado, and a number of other places, has rocks in all sizes. In fact, a major reason I bought the house where I live is because the turtle-shaped top of a large glacier-scraped granite outcrop was visible through the kitchen window.
Once I found the courage to climb to the top of an outcrop in Menotomy Rocks Park, looking down I could see Hills pond through the trees. The contours of this secluded high up spot, with blueberry bushes and natural rock arrangements scattered here and there made it feel quite magical.
Any number of these rock arrangements could be the highlight of a Japanese garden, or for that matter, arranged in a bowl of sand for indoor viewing.