Written by Education Director and Archivist, Annie Dennis
Follow Annie and Alex's ongoing project on Instagram @endangered_materials_project
After more than a century of continuous operation, Pewabic is known for a few things: our glazes (not just iridescent, but a wide range of surfaces) and our handcrafted pottery and architectural tile. We’re also known for our educational programs, which reach many within our community each year to learn about ceramics firsthand. All of that - every tile, every pot, every program - depends on materials.
It’s a wide range of natural materials that we use: metal oxides and carbonates like iron, cobalt, and copper that help create our colorful surfaces; natural clays like ball clay and kaolin that form the foundation of our clay bodies; feldspars and minerals that help glazes melt and develop their final visual character; and countless other materials that shape how ceramic work looks, feels, and functions.
We use a lot of them: materials to make our clay in our historic clay mixer, materials to maintain our signature glazes, and materials to test, experiment, and teach with. They are the foundation of everything we do.
Dry Materials, including feldspar and iron oxide (red) from the Pewabic Pottery Museum Collection, photographed by Mo Osborne
So what happens when those materials (sometimes overnight) are no longer available to us? How do we keep up with production, orders, and public programs? How do we maintain consistency across our work? How do we carry forward a legacy when the tools that built it begin to shift?
These are questions that we’ve been actively navigating over the past several years, as material shortages have disrupted not only Pewabic, but much of the ceramics industry - especially studios like ours that continue to mix our own clay bodies and glazes from raw materials.
Internally, this has required a rapid and coordinated response. We formed a working group to track availability and prioritize use across departments. Our Ceramic Materials Engineer, Alex Thullen, has led extensive reformulation efforts, adjusting and reworking dozens of our glazes as materials shift. In parallel, I found myself returning more and more to the archives - looking for precedent, patterns, and context.
Because while this moment feels urgent, it isn’t entirely new.
Ceramic Materials Engineer, Alex Thullen, in his office, photographed by EEBerger
When Mary Chase Perry Stratton founded Pewabic in 1903, there were no dedicated ceramic suppliers in Detroit. If she wanted to make pottery here, she had to build her own network for material access.
That meant sourcing creatively, often from industries that had nothing to do with ceramics.
Pharmaceutical suppliers, pigment manufacturers, chemical distributors, and mining operations all became part of that network. Materials we now think of as standard (like manganese dioxide, red iron oxide, and titanium dioxide) entered the studio through entirely different systems, often intended for medicine, paint, or manufacturing.
Pewabic Founder, Mary Chase Perry Stratton, mixing glazes in her studio from the Pewabic Pottery Museum Collection
As Pewabic’s operations grew, the studio developed its own systems and began ordering in bulk, maintaining inventories, and even supplying materials to local artists and institutions, but access was never fixed. War, economic shifts, and transportation limits repeatedly disrupted supply chains, forcing ongoing substitution and reformulation.
Looking back through historic glaze recipes, correspondence, and inventory records, what originally appeared as aesthetic evolution started reading more as a response to constraint.
A gas mileage ration receipt from the Pewabic Pottery Museum Collection dating back to the 1940s
Over time, Pewabic learned how to work within that instability.
Materials changed, processes shifted, recipes were reformulated, and the studio adapted - again and again - finding new ways to achieve the surfaces and qualities that define our work.
That approach to problem-solving has carried Pewabic through more than a century of change. It’s the same approach we rely on today.
Archival glaze recipe containing antiquated ingredients such as lead and uranium
In recent years, one loss in particular brought that reality into sharp focus: Custer Feldspar.
A foundational material in many clay bodies and glazes, it had long been a constant in our studio. When access suddenly became limited, we were left scrambling - reworking formulas, testing alternatives, and trying to maintain consistency across production and education with a material we could no longer reliably source.
It was a stressful moment! In an attempt to bring a bit of levity to it, I painted a small watercolor of a bag of Custer Feldspar for Alex. A kind of “in memoriam” for something that had quietly been a constant in our ceramic world. I knew Alex would appreciate the painting, but I didn’t expect the response it would get from others.
Custer Feldspar watercolor painting by Annie Dennis
As word spread about additional shortages and sourcing challenges, I started adding a few more (EPK, talc, pottery plaster) and other materials that were becoming increasingly difficult to find or rely on.
At a certain point, it stopped feeling like a single joke. We felt compelled to keep going - whatever this was becoming.
We began digging through Pewabic’s own material storage and nearby studios. Eventually, we turned to the broader ceramics community through social media, asking if others had materials we should document. Artists shared photographs from their own studios - some materials had been out of production for years. Many of these had little to no visual documentation online, making this exercise of community engagement critical for tracking these images. At the same time, Alex began researching these materials - tracing their origins, production histories, and shifts over time - while I continued painting. Through this process, what started as a small moment began to take shape as a growing collection. We decided to call this the Endangered Materials Project.
Education Director and Archivist Annie Dennis holding the 18” x 24” Endangered Materials | Watercolor Poster. Photo by EEBerger.
As the collection grew, it became clear that this project was part of a much larger conversation. Alex and I were able to share this work through our recent lecture at NCECA 2026, connecting current material challenges with the longer history of adaptation at Pewabic.
Today, the Endangered Materials Project includes nearly 200 paintings of materials, with many more still to come. We don’t know what the final form of this project will be, or if it will ever even have one. Materials disappear, reappear, shift, and evolve, and what feels stable is often temporary.
Looking across both our history and our present, one idea continues to surface: all of our materials exist within systems that are constantly changing. In that sense, all materials are endangered.
The Endangered Materials Project lecture presented by Annie Dennis and Alex Thullen at the 60th Annual NCECA Conference in Detroit, Michigan, on Thursday, March 26, 2026
The Endangered Materials Project remains ongoing, and we continue to add to it as materials shift and new stories emerge. A selection of these watercolor paintings is now available as prints through Pewabic’s gallery and online store.
If you have any material that you feel should be included, we’d love to hear from you. You can follow along on Instagram @endangered_materials_project
