When Rocks Speak, What Do They Tell Us?

Marcia Bjornerud's "Turning to Stone" takes us across deep time

By Sara Hashemi

January 27, 2025

Turning to Stone

Rocks speak to us, if only we choose to listen. That is the lesson of Marcia Bjornerud’s new book, Turning to Stone: Discovering the Subtle Wisdom of Rocks (Flatiron Books, 2024). Rocks hold our planet’s secrets, “each a text to be translated, a portal into the hermetic inner life of Earth.” In icy Svalbard, Norway, the patterns on limestone clasts reveal an entire history of the mountains. Eclogites, rare metamorphic rocks, are time travelers, communicating their stories across deep time.

Turning to Stone is part memoir, part geology lesson—each chapter focuses on a different type of rock, providing the scaffolding for Bjornerud to explore her journey from young girl to tenured professor. While the combination is un­expected, the evocative language and observations turn what could be a dry subject into an emotional and humorous narrative. Bjornerud entered college planning to study language or linguistics, but a required course in geology set her on a different path. Stones, she came to understand, have a language of their own that speaks to “the strangeness of the planet—its self-­renewing tectonic habits, its ceaseless repurposing of primordial ingredients.” The rocks help Bjornerud understand her own history too. The historic buildings in her rural Wisconsin community as a child were made of sandstone, and so were the aquifers belowground. Years later, in the basement of her collapsing geology department, she discovered forgotten crates of granite. “The rocks have remained as they always were,” she writes, “while our interpretations of them have vacillated and evolved. The same is true for the events of our lives; the past is immutable, but its meaning changes with time.”

Turning to Stone is a love letter to the foundations of our planet. It invites us to understand Earth’s creativity, its rituals and idiosyncrasies. “Earth doing what Earth does,” Bjornerud writes. “What a place to grow up.”