When I was a child my sister and I kept a large, flat rock under the front porch. We used it as a grinding surface to pulverize colorful rocks into rock dust. The rock dust was mixed with water and used for decorating: ourselves, bark, rocks, our siblings. I was fascinated by the different colors, some shimmery, iridescent or translucent, others matte, chalky. It was a beautiful science experiment.
I still enjoy taking rock dust, mixing it with water, and helping it become something new. Something enduring. Something longer lasting than our finger paintings washed away by the summer rain.