Before humanity mastered smelting, our only source of iron fell from the stars

Nature · Published 3 October 2026 Swipe more like this →

In short: Long before the Iron Age, ancient civilizations crafted tools and sacred objects from iron that arrived on Earth via meteorites. This celestial metal, distinct from terrestrial ores, was prized by cultures from Egypt to China. It remains a unique remnant of the early universe, still shaping our atmosphere today.

Meteoric iron is a native metal, a rare remnant of the early-universe protoplanetary disk. Unlike terrestrial iron, which is typically found in ore, meteoric iron exists in a metallic state. It is primarily composed of two nickel-iron mineral phases: kamacite, a body-centered cubic alloy, and taenite, a face-centered cubic alloy. Scientists distinguish it from telluric iron by its higher nickel content, lower carbon levels, and unique microstructure, such as the Widmanstätten pattern—lamellar structures that form as the metal cools—and Neumann lines, which are deformation features caused by high-impact events.

Before the development of smelting technology, this extraterrestrial material was the primary source of iron for human societies. Archaeological evidence confirms its use in diverse regions long before the systematic processing of terrestrial iron began. For instance, iron beads found in a Gerzeh graveyard, dated to approximately 3200 BC, contain 7.5% nickel, confirming their meteoritic origin. Similarly, artifacts from the tomb of Tutankhamun, dated to around 1350 BC, and axes from Shang dynasty China, dated to around 1400 BC, have been verified as meteoritic. In Mesopotamia, the material was so revered it was known by the special term 'an-bar' and reserved for sacred ritual objects.

The utility of meteoric iron persisted even after smelting became common, particularly in regions where the technology was absent or metal was scarce. The Inuit utilized the Cape York meteorite for tools like harpoon tips and knives, while the Nama people of Namibia worked fragments of the Gibeon meteorite for centuries. Beyond its historical utility, meteoric iron continues to influence the Earth today. As meteorites descend, they undergo ablation, releasing free iron atoms into the upper atmosphere. These atoms react with ozone to produce iron oxide, which is believed to be responsible for the orange spectrographic bands observed in the upper atmosphere.

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