Beyond Blue: Cobalt from Pottery to Cell Phones

By Darby Ronning

Cobalt is a material that many people today take for granted, myself included. Used in lithium-ion batteries, many modern conveniences run on the metal: my cell phone, my laptop, electric vehicles, e-cigarettes, cordless vacuums, and more.¹ I first started thinking about cobalt when recent news stories made public the horrific exploitation and child labor used to mine the resource in countries such as the Democratic Republic of the Congo.²

Having only known of cobalt in its modern, lithium-ion battery context, I was surprised, when, at a demonstration of historic blue transfer-printed pottery, our instructor told us the vibrant blue we were working with was made of cobalt. Of course, I knew cobalt was associated with blue, but I hadn’t put the pieces together to understand that the blue I was seeing in historic pottery was made from the same cobalt powering the battery in my cell phone.

Cobalt showed up again on our trip at World of Wedgwood, where our group was given the opportunity to see archival materials, including some of Josiah Wedgwood’s experiment books, where he varied ratios of minerals to try to improve the color in his pottery. Cobalt made frequent appearances in these books, where it was used not only to tint pottery blue, but also to add vibrancy to white lead glazes.

Once I was back stateside, and as I dug into cobalt histories on my own, I was surprised at the seeming lack of social history of cobalt and how it was sourced. Sure, I could find chemical descriptions of cobalt and its alloys, histories of its use in glassware from the ancient Egyptians to the invention of synthetic pigments, and even pros and cons of cobalt ore sourced from different countries, but I found very little on the experiences of those who dug up the metal.³

Labor can be completely invisible, especially the labor it took to source materials that make up a final product. My research on cobalt thus far is most definitely a first step in a longer effort in understanding the networks of people across the globe involved in cobalt mining, trade, and use and how exploitation often underscored manufacturing from antiquity to today.

1. “Used Lithium-Ion Batteries,” Environmental Protection Agency (EPA), updated March 5, 2025. [Click the title to access this resource, as well as the ones in the footnotes below!] ↩︎
2. Terry Gross, “How ‘Modern-Day Slavery’ in the Congo Powers the Rechargeable Battery Economy,” National Public Radio (NPR), February 1, 2023. ↩︎
3. Howell G.M. Edwards, 18th and 19th Century Porcelain Analysis: A Forensic Provenancing Assessment (Springer, 2020) and Howell G. M. Edwards and Philippe Colomban, Blue by Fire: A Marker of the Technical History of Glass and Ceramics (Springer, 2025). ↩︎