Campo del Cielo iron meteorite. Structural classification is coarse octahedrite. Weight is 3 kilograms. This photo shows wonderfully developed regmaglypts, also referred to as “thumbprints”. The regmaglypts formed while the meteoroid ablated during passage through the atmosphere. The Campo del Cielo meteorites come from Argentina, where they are believed to have fallen between 4,000 and 5,000 years ago. Nickel-iron meteorites, such as this one, are fragments of the cores of larger ancient asteroids (similar to Earths iron core), that have been shattered by impacts with other asteroids. After spending 4,500 million years in space this piece of ancient iron core found its way to Earth from the asteroid belt between Mars and Jupiter.