Figure 1. This object was not made by humans. It is an iron meteorite (Campo del Cielo), which formed ~4.6 billion years ago. There is a small (0.5 inch) ceramic magnet attached. Note irregular shape with no symmetry, no sharp edges, no right angles, no straight lines, no flat parts, no vesicles, some regmaglypts, and a little rust. Iron meteorites do not have a fusion crust, but they do have a patina. Photo credit: Randy Korotev
What you need to know
If you have a piece of metal that is not strongly attracted to a magnet, then it is not a meteorite.
The metal in iron meteorites, stony-iron meteorites, and pallasites strongly attracts a cheap ceramic magnet. Man-made iron metals, e.g., wrought iron, cast iron and dome steels, however, also strongly attract a cheap magnet.
The metal in meteorites is mostly composed of iron but also at least 5% nickel.
The metal in iron meteorites consists of two alloys that together are commonly called iron-nickel (FeNi) metal. If it looks like metal and attracts a magnet, then you have to have it analyzed for iron, nickel, manganese, and chromium to determine whether it is man-made or an iron meteorite. Very few industrial metas contain >5% nickel.
People often tell me that they can “see” nickel or that their metal detector “sees” nickel. No, sorry, it does not work like that. You cannot determine if a piece of metal contains nickel just by looking. Chemical tests are required.
Man-made metal things rarely have the shape of an iron meteorite.
It is often easy to tell that a metal thing is man-made just from the shape. Iron meteorites are rounded but not spherical. There are no straight lines, right angles, vesicle, or flat parts. I have never seen an iron meteorite that was long and thin. Also, unless it is very rusty, you cannot break an iron meteorite and it will not have broken sides. Here are some photos people have sent to me of objects that look like iron meteorites to me.
Except for the alleged pallasite, all of the photos below were sent to me by people who thought the object might be a meteorite. I suspect that many of these things were found with metal detectors. In my opinion, all this stuff is man-made.
There are a lot of pictures here because many persons have sent me photos on man-made metal things.
Figure 2. If it is spherical or circular, then it is not a meteorite. The hex nut (both sides) was found with a metal detector at a fairgrounds.Figure 3. If it has flat sides, right angles, or a geometric shape, then it is not a meteorite. Long-thin things are not aerodynamically stable and would not survive atmospheric entry with such a shape.Figure 4. If it is long and thin, then it is not a meteorite.Figure 5. Some of these things appear to have been molten metal poured onto a flat surface like concrete or the ground. Others appear to to have been molten metal poured into water or oil. Meteorites are not dendritic.Figure 6. Iron meteorites will not have holes like this exposed on a sawn surface. Note that in the upper left image there is a cotton swab with a pink stain, a positive response from the DMG test for nickel. The person who sent me this photo assumed that the positive response meant that the object was an iron meteorite. In my experience, this test is not adequate for identifying iron meteorites because it is too sensitive, which leads to “false positives.” The iron-nickel metal in meteorites contains at least 5% Ni, yet this test will be positive (pink stain) with metal containing much less Ni that 5%. Many industrial metals nominally identified as “iron” (e.g., “cast iron,” pig iron”, “wrought iron”) may contain enough Ni to generate a positive response to the DMG test. I have analyzed (by instrumental neutron activation analysis) two such samples that contained only <0.5% nickel, i.e., they were not meteorites. Figure 7. In 2022 these things were being offered for sale on the internet as pallasites found in Ohio. The one on the upper right has been filed to expose the metal. Given that (1) the pieces are vesicular (pallasites are never vesicular), (2) there are no obvious olivine grains present, (3) the seller makes no claim that the metal is, in fact, an iron-nickel alloy, and (4) the seller presents no evidence that the the material has been classified as a meteorite, I suspect this stuff is just slag. There are some photos of real pallasites here.Figure 8. These things were found on a beach in Washington state. I am confident that they are not meteorites (!) but I have no idea what they are. Any ideas? Thanks for the photos, Mary.Figure 9. Some of these things appear to be metallic but not iron (nonferrous).Figure 10. Figure 11. Figure 12. Pieces that fall off tractors and other machinery often have scrape marks and gouges.Figure 13. If it has flat sides, right angles, or a geometric shape, then it is not a meteorite. Figure 14. I suspect that these things are all aluminum, which is easy to melt. None is rusty (= not iron) and two are broken (= not iron). They all probably started out as beer or soda cans. Several are flat on the bottom side, implying that they were melted in a container and poured onto a flat surface like concrete. If, like aluminum, it is metallic but does not attract a magnet, then it is not a meteorite.Figure 15. More molten metal poured on a flat surface. None of this stuff is rusty, so it is probably all aluminum.
