American Scientist

UNDER A METAL SKY: A Journey through Minerals, Greed, and Wonder. Philip Marsden. 352 pp. Counterpoint, 2025. $29.

Travel writer Philip Marsden takes two journeys in his newest book, Under a Metal Sky: A Journey Through Minerals, Greed, and Wonder: a physical trek through old mines, museums, and trade routes across Europe; and a philosophical amble through European thoughts and beliefs about minerals, mining, and the Earth over the course of history. The title comes from a widespread belief in ancient myths that the sky was made of metal: Stars were lights shining through holes pricked in the metal, and meteorites were little pieces that had fallen off. As Marsden writes, in classical and alchemical cosmologies, everything above has an equivalent below. Seeking that connection between the minerals in the ground and the nature of the heavens via the human world in between is his goal in this text.

The book begins with a school-age Marsden’s painstaking excavation of a large ammonite, the source of (or perhaps stimulus for) his childhood interest in geology. The story then dips back into early human history with a short chapter on how mining and using ocher helped early humans develop cognitively. From there, the author visits an abandoned tin mine in Cornwall. Marsden states his intention to follow the route a tin ingot might have traveled on its ancient journey to be made into bronze—an interesting potential throughline for the rest of the book, that is unfortunately forgotten not much later. This story is followed by chapters on other minerals and metals, including Slovenian mercury, Czech radium, Bohemian aerolites (meteorites), and bronze from anywhere and everywhere, before the book closes with six pages on lithium and a few more on soil. Why the author selected these commodities is never explained, though all are minerals, metals, or rocks that have shaped human thought in different profound ways.

Marsden deftly takes the reader through the roles that each of the selections have played throughout history, emphasizing points of interest and location-specific trivia, rather than systematic coverage. Each chapter begins with a few big-picture musings on the scientific, historical, and sometimes mythological background of the commodity. This is followed by the physical journey Marsden takes, visiting mines, museums, archaeological sites, and mineral shows. Thoughtful, colorful, sometimes oddball characters stream by: a riverboat captain, a moldavite collector, a gold prospector, a professor studying Hermetic literature. Each shows, in a different way, how the Earth still exercises a deep hold on the human imagination.

Through these characters as well as his own experience, Marsden offers an extended personal meditation on how mining, minerals, and metals have influenced humans’ relationships with the Earth. He weaves in selections from classic European authors such as Goethe, the 18th-century rockhound and poet whose famous character Faust shows up in several chapters, puzzling over this relationship. Another main source of inspiration is William Blake, whose biography and engravings occupy fully one-third of the copper chapter. Says Marsden, “Blake’s words and images possess, like the greatest creations, an inbuilt ambiguity, an innate capacity to hold multiple interpretations. Hermeticism and the mystics display something similar—the power to multiply their meanings until they either confound or provide a glimpse of revelatory truth. . . . As Goethe’s Faust has its contemporary resonance, and Hermeticism its new green followers, so it’s easy to look at Blake’s Job [the Biblical figure, of whom Blake would create engravings] and see in him the collective crisis facing the planet.”

The scientific reader, unfortunately, is among those most likely to end up confounded while reading this book, instead of glimpsing revelatory truth. Despite Marsden’s evident passion and vivid descriptive writing, both of which are much appreciated, factual errors pervade the book. Mineralogists will be surprised by the statement that some 450 minerals exist on the planet, when in fact the current total exceeds 6,000. Forging and casting are also mixed up several times. Stars are the ultimate source of metals, but the author contends that “in the Sun, gold cannot be created—silver and lead can, but not gold,” which, he continues, only forms in supernovae. In fact, main-sequence star nucleosynthesis does not produce any element heavier than iron. Silver, lead, and gold all require supernovae or a neutron star merger. Other examples abound. Most of these mistakes could have been fixed with a few minutes apiece on Google. That they were not creates an overall impression of carelessness.

This carelessness undermines Marsden’s credibility as he returns again and again to the greed that minerals have inspired in humans, a central theme of the book and title—yet here, too, he gets important facts wrong. His statement that a Bronze Age copper smelter devoured 300 kilograms of charcoal for each 1 kilogram of copper produced represents a charcoal-to-metal ratio that is higher than archaeometallurgists’ highest estimates. In another section, he blames gold mining for “tailings dam failures, mercury and cyanide poisoning, and tunnel collapses [that] kill thousands of people a year.” Known fatalities in the world’s entire commercial mining sector are less than 100 per year, and mostly from coal. Annual deaths from artisanal mining are unknown. Lumping the two sectors into one category and labeling it “one of the most destructive industries in the world” is analogous to putting street-corner drug dealing together with Walgreens and calling pharmaceutical distribution one of the world’s most lethal businesses. Death and devastation on any scale are tragic enough without inflating or misrepresenting them.

Strong on impressions but weaker on facts, Marsden’s book adds up to an interesting travelogue of his physical and philosophical journeys through the world of minerals. The author succeeds in taking the reader on a tour through various interesting examples of the subtle, quasi-mystical grip that the Earth and its minerals have long held on the human imagination. What is less successful is the book’s ability to convey any real message other than a sort of vague wish that everyone could share the author's mystical regard for our home planet.