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How did nickel-iron fragments and droplets provide evidence for the origin of Meteor Crater?

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four impact craters — Meteorite crater Four impact craters of the same size (30 km [20 miles] in diameter) imaged by spacecraft on different solid bodies of the solar system and reproduced at the same scale. They are (clockwise from upper left) Golubkhina crater on Venus, Kepler crater on the Moon, an unnamed crater on Jupiter's moon Ganymede, and an unnamed crater on Mars. The images are oriented such that the craters appear illuminated from the left; the Venusian crater is imaged in radar wavelengths, the others in visible light.

The presence of nickel-iron fragments and droplets provided critical evidence for the meteoritic origin of Meteor Crater by linking the site to the physical remnants of an impacting body.

Large quantities of nickel-iron fragments, ranging from gravel size to as much as 1,400 pounds (640 kg), were discovered across a 100-square-mile area surrounding the crater. Furthermore, the discovery of thousands of tons of sand-grain-sized nickel-iron droplets provided essential clues regarding the impact process; their specific distribution and composition indicate that they condensed from a cloud of metallic vapors generated during the violent collision.1

While these fragments and droplets were significant, the case for the crater's origin was further solidified in 1960 by the discovery of coesite and stishovite—high-pressure modifications of silica—within the pit. Together, these findings confirmed the site as an impact crater formed by an iron meteoroid, validating a theory that had been argued for 27 years by mining engineer D.M. Barringer.12