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See also "Self-Test Check-List"
Most of the photos in the links below were either sent to me or are ones that I made of rocks that people have sent to me.
| # |
Checklist |
Examples |
Caveats
& Comments |
1 |
The chance of finding a meteorite is exceedingly small. | Most rocks are not meteorites. Experienced hunters can go years between finds. | |
2 |
The chance of finding a lunar or martian meteorite is even smaller. | Only about 1 in 1000 meteorites
is from the Moon or Mars... |
... and Moon and Mars meteorites look very much like some types of common Earth rocks. You can't identify a Moon or Mars rock just "by looking." |
3 |
The chance of finding a meteorite that has just fallen is even smaller. | Since 1900, the numbers of recognized meteorite "falls" is about 690 for the whole Earth. That's 6.3 per year. Only 98 of those occurred in the US. That's less than 1 per year. Even when a meteorite is observed to fall, it takes experienced hunters several days between the finding of different stones. | |
4 |
Not every rock that falls from the sky is a meteorite. | more stories | |
5 |
Not every rock that looks like a meteorite is a meteorite. | It is often not possible to determine whether a rock is a meteorite just from its appearance. | |
6 |
Some meteorites don't look like meteorites. | If someone had walked into my office with this rock, I'd have said that it wasn't a meteorite, and I've seen all but a few lunar meteorites. | |
7 |
If it does not have a fusion crust, then it's probably not a meteorite. | Some meteorites do not have obvious fusion crusts, but that's rare. Usually there's fusion crust on at least one face. | |
8 |
If it has some kind of rind or coating, the rind or coating is probably not a fusion crust and the rock isn't a meteorite. | There are numerous processes on Earth, such as chemical weathering, that cause rocks to have coatings and rinds. Some of these, particularly desert varnish, can look remarkably like a meteorite fusion crust. | |
9 |
If it's got a thick rind or coating, then it's not a meteorite. | Fusion crusts are thin because as soon as the exterior of the meteorite melts, the liquid is sloughed off because of the high velocity of travel of the meteoroid through the atmosphere. Fusion crust doesn't build up, except perhaps on the trailing side. | |
10 |
If the inside is the same color and shade as the outside, it's probably not a meteorite. | Fusion crusts are usually darker than the interior of a meteorite. | |
11 |
If it "looks burned," it's probably not a meteorite. | Meteors don't burn. Meteorites are not burned. The outside has melted, but they haven't burned and they don't "look burned." | |
12 |
If it's a big rock, then it's probably not a meteorite. | Most stony meteorites are smaller than people think they are. If you like statistics, see this. Also, see this for the masses of the >70 individual stones that have been found from the recent fall of the Sutter's Mill meteorite in California. Iron meteorites can be big, however: Willamette | XinJiang | Campo del Cielo | Hoba | |
13A |
If it's big and it does not have regmaglypts, then it's probably not a meteorite. | Not all meteorites have regmaglypts, however the big ones usually do. | |
13B |
If it has dimples, they're not necessarily regmaglypts. | Not all dimples are regmaglypts. The dimples in the photos are too deep for regmaglypts. | |
13C |
If it has "craters" on the surface, they're not craters. | Asteroids have craters, meteorite do not. The surface matetrial ablates away as the meteorite comes through the atmospher. See next. | |
14 |
If it's angular, with sharp edges or points and no smooth sides, then it's probably not a meteorite. | For small meteoroids, 90% of the mass is lost to ablation as it comes through the atmosphere. Edges, "corners,"and any other protuberances are the first parts to ablate away. Put and ice cube in water and wait for 90% to melt. The "cube" that's left will have no edges or points. It's like that with meteorites. | |
15 |
If it's stony (not an iron) and has a rough exterior, then it's probably not a meteorite. | ||
16 |
If it's stony (not iron) and has protuberances, then it's probably not a meteorite. | ||
17A |
If it's square, rectangular, or has flat sides or parallel sides, then it's probably not a meteorite. | As above, flat sides and square corners are not consistent with an object that has come through the atmosphere. | |
17B |
If it's highly oblate (flat and thin), then it's not a meteorite. | Escept for frisbees and flying saucers, oblate objects are not all that aerodynamically stable and would be break apart during the descent through the atmosphere. | |
18 |
If it has swirls, foliation, radiating features, or tubes, then it's not a meteorite. | Although there may be processes in space that can lead to such rocks, we haven't seen meteorites like this yet. | |
19 |
If it's got layers, laminations, parallel sides, or any kind of planar features, then it's definitely not a meteorite. | Layered rocks occur on Earth because the Earth has gravity. Most meteorites come from objects (asteroids) too small to have any appreciable gravity. If there is no gravity, then there is no way to form layers. Here is the only exception I know about, and it's a terrestrial weathering effect. | |
20 |
If it's got veins, particularly ones that stick out, then it's not a meteorite. | Melt veins are seen in some meteorites, but they are never linear. Rarely, there might be veins of impact melt (see NWA 482). Some meteorites have veins of metal. | |
21 |
If it's got fractures or filled fractures, then it's not a meteorite. | If a meteoroid is fractured, then it will break apart along the fractures as it passes through the atmosphere. Odinary chondrites that have been on Earth a long time, will self fracture as they metal rusts, but they will look rusty and not like the rocks in the photos. | |
22 |
If it contains elongated minerals or clasts, then it's probably not a meteorite. | Among meteorites of which I'm aware, MIL 05035 (an unbrecciated basalt) has the most elongated minerals; see photomicrograph. It is exceedingly rare for the aspect ratio of a clast in a brecciated meteorite to exceed 3-to-1. | |
23 |
If it's spherical or circular, then it's probably not a meteorite. | There are processes on Earth that lead to spherical rocks (spheroidal weathering, tumbling and abrasion in water). These processes don't occur where most meteorites come from. Here is a photo of the only exception of which I'm aware: Canyon Diablo spherules | |
24 |
If it contains round things, they round things are not necessarily chondrules. | Lots of Earth rocks contain round things. | |
25 |
If it's got lots of holes in it, then it's not a meteorite. | Very few stony meteorites have vesicles or holes. In those that do, the holes are sparse and small. See "Vesicles in Meteorites." Vesicles require gas and that the rock was once molten. Most meteorites were never molten. Iron meteorites sometimes have holes, however. | |
26 |
If it's got big holes in it, then it's not a meteorite. | Two of the photos are of rusty man-made objects | |
27 |
If it contains lots of amygdules, then it's probably not a meteorite. | Some hot-desert meteorites have terrestrial material filling rare vesicles. | |
28 |
If rock or mineral grains stand out from the matrix or have been plucked out leaving a cavity, then it's probably not a meteorite. | In many terrestrial sedimentary rocks, the clasts are often harder than the matrix. Sometimes they pop out of the rock. That doesn't happen much in meteorites. | |
29 |
If it's long and thin, it's not a meteorite | A rock with a high aspect ratio (length-to-width) is not aerodynamically stable and would break apart in the atmosphere. | |
30 |
If it contains quartz, then it's not a meteorite. | Quartz is the only common mineral that will easily scratch glass. Try to scratch glass with a sharp edge of the rock. If it makes a deep scratch, it's not a meteorite. | |
31 |
If it consists of hematite or magnetite, then it's not a meteorite. | Iron-oxide nodules or concretions are the most common kind of meteorwrong sent to us. Highly weathered meteorites may contain some hematite, magnetite, and maghemite. Do a streak test. | |
32 |
If it is glassy and vesicular, then it's not a meteorite. | It's probably a piece of slag, particularly if it attracts a magnet. | |
33A |
If the rock does not rather strongly attract a cheap magnet, then it is probably not a meteorite. | Don't use a rare-earth magnet to test for magnetic attraction. A meteorite will attract a cheap refrigerator magnet or compass | |
33B |
If it attracts a cheap magnet but you cannot see shiny
metal grains on a sawn or broken surface, then it's not a meteorite.
|
Meteorites attract magnets because they contain iron-nickel metal. Earth rocks don't contain iron-nickel metal. Many Earth rocks are magnetic, however, because they contain the mineral magnetite. | |
33C |
If the rock contains shiny things that look like metal, but the rock does not attract a magnet, then the shiny things probably aren't metal and the rocks is not a meteorite. | Some sulfide and oxide minerals look like metal. | |
33D |
If it does not attract a cheap magnet, then it could still be a meteorite, but it is probably not. | Many of the rarest types of meteorites (achondrites) do not attract a magnet, but most Earth rocks also do not attract magnets. | |
34A |
If it is made of metal or looks metallic, then it might be a meteorite, but it's probably not. | Humans have been making metal things for hundreds of years. Some minerals look metallic but are not. | |
34B |
If it looks metallic and is shiny on the outside, it is not a meteorite. | Some sulfide minerals look metallic and some non-ferrous metals are shiny. | |
35A |
If it's "heavy for it's size," then it might be a meteorite, but it's probably not. | The commonest kind of meteorites, the ordinary chondrites, contain iron-nickel metal; that makes them denser than most Earth rocks. However, some Earth rocks are dense like meteorites. To confuse the issue, some rare meteorites (achondrites) have low densities like common Earth rocks. | |
35B |
If it's not heavy for it's size, then it might be meteorite, but it's probably not. | ||
36 |
If it's reddish, particularly on the inside, then it's probably not a meteorite. | Most meteorites are shades of grays and browns; some may be reddish on the outside. | |
37 |
If it shows polygonal or columnar jointing, then it's not a meteorite. | Although jointing has been observed volcanic rocks on Mars, we haven't yet seen a meteorite with contraction fractures. Any meteorite would break along such fractures when the meteorite hits Earth's atmosphere. | |
38 |
If it's stony (not iron) and has a really goofy shape, then it's probably not a meteorite. | Meteorites don't look like this. | |
39 |
If it's hollow, then it's not a meteorite. | ||
40 |
If it does not look like other rocks in the vicinity, then it might be a meteorite, but it's probably not. | ||
41 |
If you found it on the beach, then it's probably not a meteorite. | I am aware of only two meteorites (Southampton & Lovina) that were found on a beach. | |
42 |
If you found it in a stream bed, along a river, or any other place where there are lots of rocks, then it's probably not a meteorite. | Successful meteorite hunters search for meteorites in places where there are not a lot of rocks. If you want to find your car easily, park it in an empty parking lot. | |
43 |
If you found it near a road or railroad track, then it's not a meteorite. | It may have fallen off a train or truck. | |
44 |
If the rock is "really hard," then it's probably not a meteorite. | Because meteorites don't contain quartz (the hardest common terrestrial mineral), they're not all that hard. | |
45 |
If it's in a conspicuous place, then it's not a meteorite. | Unless it's in a museum | |
46 |
If you found a lot of them in one place, then they are not a meteorites. | Meteorites break apart in the atmosphere 10 miles or more above the Earth's surface. The fragments are spread out over miles (strewn field). The chances that 2 or more land in the same spot are very small. | |
47 |
If you found it in a crater, then it's not a meteorite. | Meteorites hit the ground at terminal velocity, about 200-400 miles per hour. That's not fast enough to make a crater unless the rock is large (>meter size? I really don't know). | |
48A |
If you saw a meteor and then found a stone, then the stone is not a meteorite. | Read this. | |
48B |
If you found a rock, it might be a meteorite, but it is definitely not a meteor. | Wikipedia: "A meteor or 'shooting star' is the visible streak of light from a meteoroid or micrometeoroid, heated and glowing from entering the Earth's atmosphere, as it sheds glowing material in its wake. " | |
49 |
If you found a rock that was hot to touch or appears to have been subjected to "extreme heat," then it's not a meteorite. | Few meteorites have been collected immediately after they fell, and reports vary from "hot" to "cold." The physics of the process, however, lead scientists to favor "cold" to perhaps a bit warm for the smallest meteorites. Outer space is exceedingly cold. A meteoroid in space is very cold. It only takes seconds for a meteorite to pass through the atmosphere. Although the exterior gets hot enough to melt, the hot material immediately ablates away, so conduction of heat to the inside of the rock is inhibited. Also, rocks are not good conductors of heat. Meteorites don't start fires. The interior of a meteorites show no evidence of having been heated during the atmospheric entry process. | |
50 |
If it's been in your familiy for years, it's probably not a meteorite. | But then... | |
51 |
If your metal detector says the rock contains nickel, then it's lying. | Metal detectors aren't that smart. | |
52 |
If it's radioactive, then it's not a meteorite. | Most meteorites are less radioactive than are most Earth rocks. Only the thorium-rich lunar meteorites like SaU 169 are slightly radioactive when tested with a Geiger counter. | |
53 |
If there's writing or a picture on it, then it's not a meteorite. | ||
54 |
If it has a face, then it's not a meteorite. | Yes, this photo was sent to me by someone. | |
55 |
Many-to-most rocks sold over the Internet as meteorites really are meteorites; some are not. | There are many reputable meteorite dealers that sell real meteorites on the Internet. I have bought several meteorite specimens from such dealers. However, there are foolish or devious people who try to sell backyard rocks as meteorites. Most rocks offered on e-bay for prices >$10,000 are not really meteorites. Sometimes, cheap meteorwrongs are offered for sale, however. | |
56 |
Advertisements for alleged meteorites that are filled with meaningless, pseudoscientific mumbo-jumbo and absurdly high prices are usually selling just rocks. | Some people just don't have enough real work to do. | |
57 |
If you find a real meteorite, it isn't worth as much ($) as you think or wish. | ||
58 |
Meteorological is not the same as meteoritical. | ||
59 |
I have seen nearly every lunar meteorite but I have never found one myself. | So, why do you think that you found one? | |
60 |
Nobody can identify a meteorite over the telephone. | Don't call me on the telephone. I won't answer.
I don't hear well. I don't want to know your story. |
There is nothing you can tell me over the telephone that allows me to say "Your rock is a meteorite." I don't want to know the circumstances about how you obtained it. I want to see the rock, a photo of the rock, or a chemical analysis of the rock. The rock speaks for itself. And rocks don't speak on the telephone. E-mail me. Send photos. I might put your photo on this site. |
61 |
I can't identify a meteorite from a photo... | ...particularly if it was taken on a mobile
phone. |
Some people, however, have sent me some really great photographs. |
62 |
In English, there is only one way to spell meteorite. | I have received e-mails with meteorite
spelled many different ways: |
météorite, meatorite, medeiorite, medeorite, mederite, meorite, meoteorite, mereorite, merteorite, met5eorite, mete, meteeor, meteirite, météo, meteoite, meteorid, meteoriet, meteorit, meteoritre, meteoritt, meteoro, meteorolite, meteortie, meteoryt, meteotite, meteprite, meter, meteriorite, meteriote, meterite, meteroite, meterorite, meterote, meterrite, metior, metiorite, metoerite, metorite, metroite, metrorite, miteorite, & mrtrorite |
63 |
Suggested by Martin (an expert): "If an expert tells you
that your rock is not meteorite, then: Believe him!" |
Seek the advice of another expert, but be aware - all meteorite experts I know are so deluged with questions that they likely won't reply. I get contacted by ~100 people per month, and I have no interest in arguing with people don't agree with my free opinions. |
| *A critic of this page said, "Your definitions of meteorites are not always the same as other Scientists or Geologists, someone in your profession is Wrong!!!!!" True, in part. On the other hand, Winston Churchill is alleged to have said (about something completely different), "There are a terrible lot of lies going around the world, and the worst of it is half of them are true." Compromise: I admit that all of these statements are untrue some of the time. Also, these aren't "definitions;" they are just guidelines. |
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