"Here are images of places that I've hiked, printed with rocks that I found while hiking and ground to a fine powder."
But I get ahead of myself. First, I need to start with the basics. One "Art Night" at The Circle, our local coffee shop/wine bar, I brought a set of grinding tools and some rocks.
A couple of us worked for about 4 hours, breaking the rocks up and powdering them. It was grueling work. One of the rocks, a serpentine that yielded a grayish green, was so hard that I would never use it again. The end result was gritty instead of powdery.
At the end of the night we had a pretty impressive set of pigment powders, especially considering that I just picked up these rocks on a hike in the park. There are many more steps to making an ink, but this is a good first step and very satisfying to see.