I joined Heidi Gustafson and a dozen others for an excursion into the Oakland hills to uncover local pigments. Over the course of the day, we hiked through a redwood-flanked trail, up a rain-swollen stream, over an area once mined for pyrite, among graffiti-decorated ruins, and along a ridge overlooking the San Francisco Bay.

Aside from the magic of finding pigment just lying around on the ground (!), the hike itself was a grand adventure. I saw an actual albino redwood, the ghost trees I was enthralled by after hearing the Science Solved It podcast about them. Little green blades and cotyledons were sprouting up everywhere after a week of rain. I pulled a tiny knob of gum from an acacia tree arching over the path. A few steps went through a perfume cloud of sage.

Along the hike, Heidi shared information on Ohlone culture, ochre-based traditions, and interesting bits about local history and geology as everyone collected colorful rocks that had pigment potential. Bright yellow and red ochres stood out against the path and surrounding landscape; their crumbly texture differentiating them from the hard, gray angular stones around them. To help identify ochres, we swiped the rocks on a small bar of unglazed ceramic tile. The streak test shows a little stripe of the powdered mineral, revealing the color.

my streak plate covered in pigment samples

Post-lunch, we went to a large rock formation that was rich with pigments—green serpentine, yellow goethite, and red hematite—for a final search. After dividing our collection into piles that were similarly colored or produced matching streak tests, small amounts of pigment were smashed with a mortar and pestle.

I gathered an olive green, mustard yellow, and a range of reds: deep maroon, brighter sienna, and mauve rose. Others found peach, cream, browns, bluer shades of green, and more. Some participants ground and tested other materials they had collected on the hike: white kaolin clay, red brick, and blue-black charcoal from a campfire.

Ochre Spectrum

After pulverizing and sieving our rocks, we took a pigment group photo, documenting the hidden rainbow in our backyard.

Back at the studio, I ground the remaining serpentine into a powdery pigment, which Jessica mulled into a beautiful, soft, celadon green watercolor paint. The handful of little rocks picked one by one from a cliff wall has been transformed into a delicate and romantic wash of color on paper.

This was a day that I won’t forget. I am so thankful to have had the opportunity to gain new insight into art materials and the paintmaking process while immersed in nature.

About Early Futures

Heidi, describing herself as an ore whisperer, runs a research studio and ochre archive in Washington, where she collects, studies, and preserves iron oxides from around the world. Her extensive knowledge, ease with sharing that expertise, and reverence of the land makes apparent her deeply personal connection to her work.
On the web: earlyfutures.com
On Instagram: @heidilynnheidilynn

Originally posted to the Limn Colors blog, which I have closed.

Pigment Hunt: Oakland, CA