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I may have found a couple of meteorites

  1. Sep 24, 2011 #1

    Ivan Seeking

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    Because our creek moves a great deal of rock, I've been meaning to work it with a metal detector during the summer months when it's dry, for a long time now. It seems likely that a meteorite would get deposited on the property during heavy flows, from time to time. A friend finally loaned me his detector so I gave it a go. Within an hour I found three possible candidates, with one quickly ruled out as it's not affected by a magnet. The other two are looking somewhat promsing. I've been reviewing the various tests that one can do at home, but suggestions are appreciated.

    I've done rub tests and visually inspected them to see if they could be magnetite or hematite. So far they seem to look more like iron meteorites than anything else. I just tried using a file on one surface of each and put them in vinegar. I don't know if the low concentration of acid will be enough to work with time, but I know from previous reading that stronger HCL will leave a dististinctive cross-hatch pattern in some types of meteorites, so I'm hoping vinegar might be enough if left to soak long enough. If not, perhaps muriatic acid will work? I haven't spotted the required concentration yet. Maybe I'll need to get something stronger?

    I started with this site as a reference.
    http://static.arxiv.org/pdf/1109.4897.pdf

    One find is just a pebble really; pyramidal in shape with about a 0.5 x 0.5 inch base. The other candiate is more like 1" x 2" x 0.75" in size.
     
    Last edited: Sep 24, 2011
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  3. Sep 24, 2011 #2

    Evo

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    That is so cool, I hope they are meteorites!!!
     
  4. Sep 24, 2011 #3
    "Muriatic" is another name for hydrochloric acid.

    I buy it by the gallon as a cheaper and better version of CLR (Calcium-Lime-Rust remover). It's sold by the gallon for killing bacteria in swimming pools.

    I've played around putting nails and pieces of aluminum in it, and it starts to attack them pretty readily. It gives off hydrogen gas, and the acid starts to become to a chloride of the metal.

    The stuff sold for swimming pools is already dilute. If that's what you have, practice on nails to see how long to leave it in before the surface oxidation is removed. That may only take 5 seconds or so, depending on the nail. The generation of hydrogen gas will be immediate and completely apparent.

    On the other hand, vinegar can be turned into very weak hydrochloric acid just by adding common table salt. This will require a lot longer "soak". You will barely be able to see any gas bubbles forming. That may be the safer way, though.
     
  5. Sep 24, 2011 #4

    Ivan Seeking

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    Yes, I knew that Muriatic acid is just the commercial name for relatively dilute HCL, but you make a good point. I too played with muriatic acid and aluminum foil [a long time ago] and it did react readily and strongly for an off-the-shelf home product. That should be enough for the test that I've seen done. I can use the rest to clean my driveway. :biggrin:

    I don't think I've ever heard this. I'd have to go back to my college chem book.. I guess that makes sense... but instead will take your word for it. With time, even a very dilute solution would work, I would think.
     
  6. Sep 24, 2011 #5

    Ivan Seeking

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    Whoops, the link I provided earlier may not be the best source for identifying meteorites. This is the link I meant to post.
    http://epswww.unm.edu/iom/ident/index.html [Broken]

    Both rocks appear to have a fusion crust, and both are very dense. Also, the rock that produced the hit but failed the magnet test, does not have the dark crust. I went to check the density but my old triple-beam took a hit somewhere along the line and I didn't know it. I'll have to fix that before I can check.

    Also, I incorrectly said it looks like an iron meteorite. I should have said stony meteorite.
     
    Last edited by a moderator: May 5, 2017
  7. Sep 24, 2011 #6
    I don't know the chemistry behind it, but it's the old "clean the copper" technique you find in lists like "How To Clean Anything!"

    Also in chemistry demonstrations for kids:

    http://www.chem.umn.edu/outreach/card-saltvincopper.html [Broken]

    It's HCl, so it also interacts with other metals, of course.
     
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  8. Sep 24, 2011 #7
    Did you try the "streak" test?

     
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  9. Sep 24, 2011 #8

    DaveC426913

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    Cool.

    Every once in a while, when I come across a farmer's field with a stone wall, I try to examine it for possible meteorites. It works well in England, where there are miles and miles of stone walls, from centuries of farmers clearing their fields of stray rocks. (A trick I learned from a Paleo/Geology girlfriend many lifetimes ago)
     
  10. Sep 25, 2011 #9

    Ivan Seeking

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    Yes I did, but the first time I tried it on somewhat coarse cement and saw nothing. Last night I decided to take the suggestion from the page and tried it on the inside of the toilet lid. This time there was a distinctive gray streak. This suggests that it's magnetite. But the streaks were light gray, not dark gray, so I'm going to hold out for the density test before calling it a wash. At this point, unfortunately, I would have to say they are likely magnetite.

    I thought I had already ruled out magnetite with another test... I need to back and review the web pages. Maybe it was the first streak test that I had in mind.
     
  11. Sep 25, 2011 #10
    See if the suspected magnetite is, itself, magnetic. Will it attract small bits of steel/iron?
     
  12. Sep 25, 2011 #11
    Regardless, I wouldn't give up with the metal detector.

    I got a cheap one, myself, at the swap meet years ago and determined to go down to Pacific Beach early in the morning. When I got there I found twenty other people with metal detectors.

    You, on the other hand, have "virgin" territory to explore, and you never know what you might find.
     
  13. Sep 25, 2011 #12

    Ivan Seeking

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    No, it is not magnetized, but I couldn't remember if this is definitive for ruling out magnetite.
     
  14. Sep 25, 2011 #13

    Ivan Seeking

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    No doubt, I'm really into virgin territories. :tongue2:

    Seriously though, I've seen what this creek can do when we have a lot of rain. It can trench down six feet into hardpan in a few hours, and move rocks over 80 lbs. After we had a 500 year flood, I found one ~ 500 Lbs tree stump in my pasture! So it's like a little time machine feeding from the hills above and beyond us. That's what motivated me to start looking. And beyond meteorites, gold is another likely find. We have tons of quarts coming in and on our own property - we have collected buckets full of that, tourmaline, agate and other interesting and semi-precious stones. The creek also has lots of black sand, and even blue water at times, both of which can indicate the prsesence of gold.
     
  15. Sep 25, 2011 #14
    I meant to go gold panning up in Julian all summer, but never made it. Anyway, there are a few dozen youtubes on how to pan. It's also a good idea to learn how to recognize a diamond because people are said to find them occasionally when gold panning. As you said, things can get moved very far from their source. There is a known huge diamond field in Canada.
     
  16. Sep 25, 2011 #15

    Ivan Seeking

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    This area was heavily affected by the Great Missoula floods. So deposits coming directly from as far as Montana, can be found here. Even today one can find huge boulders still standing in the middle of grasslands and farmland, where they were deposted over 10,000 years ago.
     
  17. Sep 25, 2011 #16
    So, considering that, and all the quartz, it is well within the realm of possibility that you might find gold dust, even nuggets. No telling what you might find.
     
  18. Sep 26, 2011 #17

    Ivan Seeking

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    For years I was collecting the pieces to an old truck - last registered in 1938...or was it 48??? old in any case - one part at a time. One year I found a license plate, then a leaf spring, and I think a steering arm. For the next ten years or so I continued to find a piece here and a piece there when we'd walk the creek each summer. The joke was that, eventually, I'm gonna rebuild that truck!

    I actually have both license plates, so I'd even be legal.

    I was thinking it was from the 30s, but now, 1956 comes to mind. I'll have to look again.
     
    Last edited: Sep 26, 2011
  19. Sep 26, 2011 #18

    Ivan Seeking

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    Okay, self-magnetized is definitive for magnetite, but not necessary. However, interestingly, in all the photos that I've seen, the magnetite is much darker and rounder, and more porous than this piece. So far I haven't seen any examples that look the same. It is described as black. I certainly wouldn't call my sample black. At most, dark gray. After filing on the small piece, it was clear that the material under the crust was a much lighter gray color.

    Hopefully I can get my scale fixed tomorrow.
     
  20. Sep 26, 2011 #19
    That'd be funny.
    Might be a hunk of cast iron. If you have any cast iron implements in your kitchen you might take some sandpaper to the bottom of one till you get down to the uncoated metal, which, you'll see, is actually a medium grey with very distinctive grains visible. I had to machine some cast iron once. It doesn't form a "chip" like steel, but comes off in granulated form, and the newly exposed surface is much lighter in color than I suspected.

    Now, I'm also wondering what the sample was that set off the metal detector but wasn't attracted to the magnet. Brass? Copper? Platinum?
     
  21. Sep 26, 2011 #20

    Ivan Seeking

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    I seriously doubt that. It certainly appears to be a stone of some kind. I'll post some pics later when I have more time [gotta get back to work now].

    I'll include that one in the photos. Also, by tonight I may have had a chance to fix the scale and get a density measurement.
     
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