Oliver Evans chapter president, Christopher R. Dougherty, has a recent article posted on the Hidden City website. The website is known for Exploring Philadelphia’s Urban Landscape.

From Arctic Stone to Aluminum Skies: Cryolite, Philadelphia, and the Geometry of Industrial Power
August 13, 2026

The recent fixation on Greenland’s mineral wealth presents itself as novel: a 21st century convergence of rare earths, Arctic security, climate anxiety, and geopolitical rivalry. Yet, this attention revisits an older extractive arrangement. Long before critical minerals entered strategic stockpiles and policy architectures, Greenland was already bound into American industrial power through a single, improbable material: cryolite. That connection ran decisively through Philadelphia, where industrial necessity, rather than geopolitics, first drew Greenland into an American supply chain.

Cryolite—a rare mineral from Greenland, played a central role in Philadelphia chemical giant Penn Salt’s production of soaps and lyes, and later aluminum. The mine also became entangled in the geopolitics of World War II.

Dougherty has a number of other articles posted on Hidden City. https://hiddencityphila.org/author/cdoc/