We did this project last week as part of our Festival of Stones. I had envisioned a nature walk where we would gather large stones to wet felt around, but alas, there are very few locations that I could find that had stones that would fit the bill and where we could legally gather them (our state parks, for example, do not allow you to take rocks, which I completely understand). So, I ended up buying a bag of stones at the craft store (although, I'm not at all convinced that those stones were any more ethically gathered than if I had picked them up off of public land myself...c'est la vie).
The soft wool, the warm bowl of water, the slick soap...this was a wonderfully tactile experience to warm us up on a cold almost-winter morning. The motion of gently transferring the wet stone from hand to hand was incredibly meditative. We followed this tutorial and had great success. I needle felted a spiral of stars onto my stone and as soon as he saw them, Silas declared that his was in need of a moon.