Interesting how when I've been wondering about ideas for decorating, Y tube seems to read my mind...
So there's no indication in this video, how much is natural vs how much is a mix or not. But I can see how it could be made completely out of quilting cottons, +/- a heavier backing that might be something like burlap so that it will keep its shape and have a little mass.
I think it would be harder to find and scavenge wool to use for this idea, but I can imagine doing so if the opportunity arose.
I've started the video at the point where the artist is laying out her plan:
I can totally see this sort of idea beside a bed, as she did it, or if out of absorbent materials, for a narrow bathroom. No, I don't use iron on stuff as she mentions at one point, but I do know how to baste! In fact, in my opinion, hand stitching the rocks to a light backing, then quilting the whole thing to a heavier backing, would appeal to me more than seeing the stitching around each rock.