![]() Iron-nickel metal in meteorites also has high concentrations (by terrestrial standards) of rare metals like gold, platinum, and iridium. The metal in meteorites also contains a few tenths of a percent cobalt the nickel/cobalt ratio in meteoritic metal is usually in the 10-25 range. A positive response from a nickel allergy test kit ( below) is not sufficient to prove that the metal contains enough nickel for the metal to be of meteoritic origin. It requires a chemical analysis to determine if the metal contains enough nickel to be consistent with a meteorite. You can see iron-nickel metal, but it is impossible to determine if the metal contains nickel just by looking. Many people tell me that they can “see” nickel in their rock. Neither alloy occurs naturally in Earth rocks, so a natural rock that contains kamacite or taenite is a meteorite. The metal occurs as two different alloys known as kamacite (lower nickel concentration) and taenite (higher nickel concentration). “Iron-nickel” means that the metal is mostly iron but it also contains 5-30% nickel. As a consequence, meteorites have concentrations of nickel that are much greater than that of nearly any terrestrial rock. More than 95% of all meteorites contain iron-nickel (FeNi) metal. In proper hands, a hand-held “ XRF gun” can, nondestructively, provide concentrations of Fe, Ni, and Co that might provide compelling evidence that an iron meteorite is, in fact, an iron meteorite. I recommend testing for Cr and Mn because most industrial (man-made) iron contains higher concentrations of these elements than does metal in meteorites. If the metal contains more than 0.05% chromium or manganese, then it is not a meteorite. A metallurgical testing lab can provide this analysis. If you have a piece of metal that does attract a magnet and want to know if it is an iron meteorite, then obtain a chemical analysis for the elements iron (Fe), cobalt (Co), nickel (Ni), chromium (Cr), and manganese (Mn). If you think you can “see gold,” then it is not a meteorite the “gold” is probably just pyrite. Meteorites do not contain visible grains or chunks of nonferrous metals like aluminum, manganese, chromium, copper, brass, or gold. If you have a piece of metal or a rock that contains metal but it does not attract a cheap ceramic magnet ( ferrite), then it is not a meteorite. The metal in meteorites strongly attracts a magnet. Back to Some Meteorite Realities Take-home message
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