This complete stone meteorite, found in the northwestern Sahara Desert, exhibits both orientation and a rich black fusion crust.Īlthough rarely evident on the surface, most iron meteorites will reveal a remarkable interlocking pattern of intricate crystals when cut, polished, and treated with a mild solution of nitric acid. Perhaps 1 in 1,000 meteorites will exhibit a natural hole, and they are very highly prized by collectors for their aesthetic beauty. Occasionally a natural hole will form in an iron meteorite, when a portion of its surface melts completely through during flight. The few iron meteorites that have been recovered shortly after a witnessed fall exhibit an attractive bluish-black gunmetal color - a testament to the extremely high temperatures they endured during their brief, fiery flights. Only a freshly fallen iron will exhibit fusion crust, as the layer will decay quickly in Earth's moist, oxygen-rich atmosphere. Tiny fragments hitting larger ones sometimes create impact pits, which look like miniature meteorite craters.įusion crust - a burned, dark, paper-thin rind on the outside of meteorites - is fairly common on stones, but rarely seen on irons. These fast-moving pieces travel together and may crash into one another. Many or most meteors break up as they hit Earth's atmosphere, creating multiple shards as a result of explosive fragmentation. This small impact pit was caused by two fragments colliding with each other during flight. These fine patterns may be as thin as the strands of a spiderweb and might only be clearly visible through a loupe or magnifying glass. Caused by melting during the meteorite's flight to Earth, they are not present in terrestrial rocks, though similar features can sometimes be seen on common stones in the desert, and are the result of wind-blown sand gently eroding exposed surfaces.Īs a meteorite burns on its descent through the atmosphere, some of its molten surface forms droplets that move in tiny, delicate rivulets called flow lines. Thumbprints, known scientifically as regmaglypts, are small, rounded indentations found on the surface of many irons. A number of these features are also evident in stone and stony-iron meteorites, though they tend to be more pronounced in irons. The following surface characteristics make irons much easier to spot in the field. Statistically, seven times more stone meteorites are seen to fall to Earth than irons. Hikers, rock hounds, and relic and treasure hunters sometimes come across strangely shaped metallic masses in the field, and a number of meteorites completely new to science have been discovered accidentally in this manner.Įven though iron meteorites are more obvious to the untrained eye, they are actually much rarer than stones. This means irons are more likely to be found by chance by people not actively looking for meteorites. Iron meteorites are generally easier to identify than stone meteorites due to their unusual shapes, surface characteristics, and high density. Even though it was picked up years after the fall and has started to oxidize, it still shows well-formed thumbprints (regmagylpts) and some remaining fusion crust. This iron meteorite was seen to fall in the Sikhote-Alin Mountains in eastern Russia in 1947.
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