Tumble Sanding-- with river rocks?

I was just doing a little advance work on a "Ten on Tuesday" topic when I came across something interesting-- and relatively new, too, I think.

For those of you who tumble sand (or are looking into the possibility), you might want to check out Desiree McCrorey's latest "article" on the subject. She writes that she's switched from sand paper to river rocks!

Very, very interesting stuff!