[This waterfall is about 30 inches high to give you some sense of scale]
The stone that I am really praising here is the flat stone that lies in the bottom of this stream that I have built. When laying this stone in a fish-scale type pattern the stone enables me to create realistic stream bottoms, ripples, movement, and sound . . . keys in building realistic streams.
The addition tumbled stone in several different sizes adds to the realism of the scene. This illusion leaves the viewer with the thought that just maybe this is real.
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Addendum: You can find an entire series of unsorted pics of this job on the Fotki site. This link will take you directly to the page where the job photo’s are. Includes construction pictures, after pictures, and pictures from 1st Winter.
The above stone is mostly Ohio Toprock(sandstone), the round material is from a sand/gravel quarry. To give you some scale the waterfall drop is about 30 inches.
The Whispering Crane Institute 
Very natural looking–more natural looking than almost every other water feature I’ve ever seen. You really do wonderful things with rock!