Update to adventures with Feral Watercolor: a few weeks ago I discovered a gorgeous purple outcrop of rock in the Tucson Mountains—Brown Mountain, to be specific.
I processed a few pieces (my equipment and techniques are described here), and it turns out to be remarkably similar to the famous Clearwell Caves' purple ochre (4500-year-old British pigment-mining area).
Recently I was able to make it back out to paint the site in my journal, with paint made from pigment collected onsite. A first in the Feral Watercolor project.
Next up: magnetite-and-mica pigment from the Santa Catalina Mountains—and some studio paintings of places made from site-collected pigment.