Figure 8-46 Iron Meteorites (a) Irons are composed almost entirely of iron-nickel minerals. The surface of a typical iron is covered with depressions resembling thumbprints created as the meteorite’s outer layers vaporized during its high-speed descent through the atmosphere. This specimen was found in Argentina. (b) When cut, polished, and etched with a weak acid solution, most iron meteorites exhibit interlocking crystals in designs called Widmanstätten patterns. This meteorite was found in Australia.