Meteorites and Meteor-wrongs

My role as Planetarium Astronomer includes answering astronomy questions from the public over the phone, by email, and in person.  Thus, it is up to me to examine meteorite samples brought in by the public.  Or, I should say, “meteor-wrongs,” as none of the samples brought in since 1996 (when I began doing this) have actually been meteorites. 

First, let’s define some terms.  A rock which is about to enter the Earth’s atmosphere is a meteoroid.  Someone who happens to see it as it is falling, and thus sees a streak of light in the sky, sees a meteor.  Once the rock has landed, it is a meteorite.  Most meteors that we see burn up completely in the atmosphere and therefore never land as meteorites.  A meteorite, then, is a rock which originated in outer space.

which is a meteorite?

Can you tell which of these is a meteorite?

If you have a sample you believe came from outer space, here are 4 simple tests you can do at home.  Note that passing these four tests will not guarantee that your sample is a meteorite; they serve primarily to eliminate ‘meteor-wrongs.’

1) Is the sample heavy for its size?  Meteorites are denser than Earth rocks; they have more mass per volume.  A meteorite will be heavier than an Earth rock of the same size.

2) Does the sample attract a magnet?  Most meteorites found and brought in are iron meteorites.  Even the stony meteorites, which are more common but rarely reported because they superficially resemble Earth rocks, have some iron in them.  A meteorite sample, then, should attract a magnet.  Any magnet, including the ones on your fridge, will suffice for this test.

3) Is there a dark fusion crust? Upon entry into our atmosphere, a meteorite acquires a thin ‘fusion crust’ because its surface melts under the heat of entry.   This crust is black when the meteorite is freshly fallen but may turn brownish due to weathering and rust.  Bright colored or silvery samples are not meteorites.

4) Does the sample have bubble holes?  Many volcanic rocks on Earth have these holes, which form when a bubble of gas or steam expands as the rock solidifies.  A meteorite, however, is never fully molten (only the surface melts on entry into the atmosphere).  Thus, a meteorite sample is a solid hunk, without tiny holes or perforations. 

hole-y

The many large holes in this rock
are a big clue that it is not a meteorite.

So, which of the four is a meteorite? If you go back to the first photo in this post, you should be able to see holes in the top two samples - so those are out. And the bottom right is bright and silvery = not a meteorite. So, the winner is the smallest of all four, in the bottom left.  

For more information, surf to: http://meteorite-identification.com/ ,  http://meteorite.fr/ (the site is in English, too), or http://meteorites.wustl.edu/meteorwrongs/meteorwrongs.htm

24 thoughts on “Meteorites and Meteor-wrongs

  1. I found a rock in Castle Rock Lake, Wisconsin. It looks just like the one you have picured on the left top corner. What kind of rock is it?

    Thanks,
    Abbey

  2. According to our geologists, the upper left sample is simply industrial slag (waste).

  3. Hello, I have a rock like the one upper right. It is very heavy. Not magnetic. It was found in a farm field, seems out of place. What is that rock. Thanks Harry

  4. Hey Harry,
    I found one of these too, on a farm in County Cavan, Ireland, what is it?

    I was hoping it was the huge meteorite that ell here in Feb 4th.

  5. According to our geologists, the upper right sample is basaltic rock from a lava flow.

  6. Hi there, i have a few rocks that look very similar to the one on the bottom left, they are dense for their size, they all have silver specks inside of them, a few of them are magnetic, but they all fail the streak test. I have photos, where do i send them

  7. I found a rock that is about 3 to 4 lbs, way to heavy for its size. The outer texture looks like the rock at the bottom left. It is magnetic but it has little hole on it and in the hole there is somethin like little bubbles and they look silver and some are like a dark blue color. Can it still be a meteorite

  8. Hello, me and my dad found a rock in our back yard about 2 days ago, Its heavy for its size and its magnetic also has sertain spots that are brownish… But there’s one problem on one side its got holes and the other its not? Im not sure but I really think its a Meteor rock. Ill send pictures to anyone who studys thies rocks but reply with your email and ill send them to you =P

    Spencer

  9. hi, I found a rock somehting like the one pointed on the upper right side of the picture it is very heavy a bit browninsh in a few places if examined closely and it’s magnetic….could you please give me your opinion…within a mail botzma@yahoo.com

  10. i know i found a meteorite its a normal rock like one magnetic n brownish colors n one thats is made of a differnt type of metal probaly nickle real heavy with what apears to be shock wave like formations on the surface email me sarahsohrabian@yahoo.com

  11. I have what I think is a meteorite. It is extremely dense, has small porous openings that have shiny surfaces inside. It looks almost identical to the kamennoo meteorite that can b found on google images. Tried to cut i with a bandsaw with tngsten carbide blade and took every tooth off blade. managed to cut less than an eight inch. Brand new blade. It is non magnetic and doesn’t pick metal up with a high end metal detector. It has an outer gem that is witish yellowish. mayby olivine? I don’t know, kamennoo meteorite search only brings up pic and the rest in german I think. Can anybody help? E-mail me: BrandonG504@yahoo.com

  12. Hi there, I have a weird rock/stone that I found while walking through a bush track 12 years ago. I forgot all about it until I went through some old storage boxes and there it was. I remember too why I picked it up, I heard a very strange thud on the ground and there seemed to be like some sort of weird trail like a skid mark and then this rock at the end of it. I have a picture of it you can view it here http://s1048.photobucket.com/albums/s361/Ryuknite/. It seems heavier than it looks it fits in the palm of my hand yet I cannot hold it for very long because of it’s weight. Also I tried your magnetic test it is only slightly magnetic, shows a little browning on the rock but not much more like a gold colour than brown and has a weird shape to it. No holes is very dark coloured and quite smooth.

  13. Hi Richie,

    We are on it! We’ll email you if we’re able to ID your stone.

    Cheers!
    Caroline

  14. Ok, Thanks Caroline.

    Also I’ll take more pictures of it in the sunlight and will post it on here. If you need a sample I’ll try chipping some off the rock and will send it just email me the details. I really would like to know what this rock is.

  15. There is a large heart shaped, brown and white rocks, look melted together to make the heart shape. photobucket.com/album5/p594/MelissaAD/

  16. i really dont think that everything he says about what a METEORITE would all be what is said on here i mean think about it the universe is a big place with billions and billions of different types of rocks floating out there and not all are going too have the same stuff in them so magnitic or not holes or not colors or not does not mean it is or is not a METEORITE think about it lol i found something in my yard that was not there afew days ago but it was there when i found it i dont live near volcanos so thats out i dont live close enuff too plants or factorys and there is nothing else in the yard that even comes close too what this looks like it looks like it has been melted its got colors in it that i seen in pics of METEORITES that i googled its pretty lite waight and it has holes in it but not all the way through it so honestly i do not know what it is that i found but if it is a METEORITE i wish i could get alot of money for it lol

  17. I have read your report on your theory of how you believe, but in the law of physics the meteorite, right before it enters the atmosphere, it hits an outer layer of ice water before
    it hits the ground, so you see, it does appear that your theory is incorrect.
    Thank You

  18. I found a rock that is heavy for its size. It is about 2 inches by 1 inch. It is like the ones on the left; it is as black as the top-left one. It is not magnetic or at least not very magnetic. If it has a fusion crust then I cannot detect that. So it is probably not a meteorite. Can you suggest somewhere in the Los Angeles area to take it to? The California State University (CSUN) is the most convenient for us. Would the Griffith Park Observatory be good?

    Thank you.

  19. im 14 years old and found this rock by the great salt lake in utah by the salt palace and salt palace boating docks. it passed all the tests but i still dont know wether its a meteorite or a rock. im supposed to identify a rock for science but when i googled igneous rocks i found nothing like it until this website showed up. it is magnetic so i know its obviously got metal. it is also kindof rusting because i washed it to get allthe dirt off so i could be sure about the color. i need as much info about it before the 17th of april but id still be interested about identifying it after. if any one could help me at all that would be cool. i put my moms email adress on there so if you email me make sure you say its to lexis. thanks.

  20. I have a rock that appeared in my back yard. It doesn’t look like any of these… Closest one to it would be the one you say is not a meteor only this one doesn’t have holes but rather bubble shaped indentations all over it about a quarter inch in size each. It is dark crusted, it is magnetic and it appeared out of nowhere…

  21. I have a rock that looks kind of like the one above, it also looks like some of the non-magnetic rocks shown. My fridge magnet does not stick to it. However, I mowed this lawn for a lady every week, no one ever went in her back yard, it was mostly shady with trees all around. when mowing I discovered a big broken branch on the ground, there was no storm that week since I previously mowed, but I could see above where it was broken off from the tree. When I removed the branch I saw a rock embedded in the ground too high, I would have hit it with the mower. I picked it up, it was heavier than a rock, when I turned it over it had leaves, previously mowed grass stuck to it. It seems clear to me it came from the sky. When I went to Cape Canaveral Florida they had some meteorites in glass cases with prices on them, what I found looked just like the ones in the glass case, I estimated at that time based on the size and their prices that mine would be worth about $ 10,000.00 so I keep it locked up at home, but never had it tested. Not sure what to do. It looks like it might be a piece of a larger one because the poors are only on one side, it has a faint rust cooler on some of it. It has some running lines and inside some of the poors look like shiny specs of glass.

  22. Have an interesting one, I hope you can help us with. This rock is 15x11x10, weighs in at 174.5 pounds, passed the magnet test, has what looks like someone took a finger and ran it through like clay (multiple spots). Some indications point to just another Earth rock and others don’t. It was dug up in MN on Friends land and is so out of place with everything else found. Nothing even comes close to the look of this. Any ideas? Here are the pictures. http://s328.photobucket.com/user/eidenn/library/

  23. Taking the 15X11X10 to refer to inches, and converting these customary units to grams and cm, I estimate a density of 2.9 g/cm^3 for your sample. This is most likely not a meteorite, as all but the rarest meteorites have a density greater than three.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>