Iron meteorites consist almost entirely of nickel and iron and are thought to originate from the cores of ancient, differentiated asteroids. In the early solar system, these large asteroids underwent internal melting, causing heavier elements like iron and nickel to sink toward their centers—much like the Earth’s own core. Over time, catastrophic collisions shattered these bodies, sending fragments hurtling through space until some eventually landed on Earth as meteorites.

One of the most striking features of iron meteorites is the Widmanstätten pattern—a distinctive interlocking crystalline structure of nickel-iron alloys that can be revealed through careful acid etching. This process requires expert preparation, including stabilization, slicing, and polishing, as even slight errors can damage the specimen. The pattern itself is often called the meteorite’s “thumbprint” because it is entirely unique and cannot be replicated in laboratory conditions. Its formation requires incredibly slow cooling—about one degree Celsius every 10,000 years—making it a visual testament to the vast timescales and processes that shaped our solar system.