[meteorite-list] "not the best place to hunt meteorites"
Jerry
grf2 at verizon.net
Thu Feb 21 22:33:12 EST 2008
Lasse,
That's neat and simple but I learned that magnets can be deceptive in that
there's an ungodly amount of terrestrial iron in the rocks here in New
England. [maybe these here parts was never molten, ye think]
But It's a good 1st step.
I've yet to employ my newly acquired metal detector that Rubin used so
successfully out west so I'm all talk at this point. But I did become
discouraged after sending several magnetic samples off for testing before I
learned how to recognize most meterorites in the hand.
Jerry Flaherty
----- Original Message -----
From: "Lasse Lindh" <3l at comhem.se>
To: <Meteorite-list at meteoritecentral.com>
Sent: Thursday, February 21, 2008 3:45 PM
Subject: Re: [meteorite-list] "not the best place to hunt meteorites"
> Hi Michael and all
>
> We have had quite a lot of discussion about neodymium magnets for
> hunting on Skyrock Cafe. Some of the members there have used that method
> for some time. It does work quite well. In have a neo on a monopod stick
> with 40 kg pull force. But I was not satisfied with this solution
> because the chance to miss that little chondrite or iron is too big when
> using just one small magnet, so I desided to make a rake like you have
> done. This rake is bit larger and have wheels for easier pull and to
> keep the magnets off ground so they won't wear down too much or the duck
> tape that protects them.
>
> This is a 3D drawing of my Neo Meteorite catcher... ;o) It's slightly
> modified the wheeled rake by using five 4 inch neo magnets with 140 lbs
> pull force. That allows me to cover just over 2 feet search area at the
> same time.
>
> http://www.swedbird.com/meteorite/met_mag.jpg
>
> Regards
>
> Lasse
>
>
> Michael Murray skrev:
>> Hi List,
>>
>> (This is somewhat of a rehash of information I have posted before)
>>
>> If the meteorite hunting bug has landed on your shoulder but you think
>> the area you live in is not the best for finding meteorites, you should
>> give my hunting method a try. You could be pleasantly surprised at what
>> you come up with. I went to a local hardware store a few years back and
>> purchased a shop magnet cane. It has a wooden handle about 40 inches
>> long with a ring magnet on the bottom that is sandwiched in between two
>> plates of steel. I also purchased a couple 2" x 2" x 7mm neodymium iron
>> boron sugermagnets which I placed very carefully side by side on the
>> trailing edge of the bottom steel plate. Please note: If you attempt
>> this beware, strong magnets like that can injure your fingers quite
>> easily. Use plenty of caution. I put the cane in a vise so it could not
>> move before attempting to place the first magnet on. The second magnet
>> was a bit harder to get into place until it got close enough to the first
>> one.
>>
>> I have drug my magnet cane all over the place, mostly wherever there are
>> gravels. I have not had any of my finds substantiated by experts.
>> None-the-less I have come up with some very possible "suspect" stones.
>> Some are what I believe are irons and some stonys. A couple suspect
>> stonys I found in dirt not gravels. This is what leaves me to believe
>> that even if you might not think hunting in your area would be very good,
>> you may still find that the magnet will find them anyway. The smaller
>> objects falling to earth most likely will not penetrate very deep into
>> the soil when they hit. Some not at all if the surface is somewhat hard.
>> Erosion can also expose them over time. I live in an area where a river
>> cuts its way through the valley. I have found that the river gravels
>> contain quite a few of what I term "suspect" stones. I suppose the
>> reason for this is that in time, due to constant washing from snow runoff
>> and forceful rains, a lot of small material finds its way into the river,
>> including meteorites.
>>
>> It takes a little time spent looking close at local rocks to get to where
>> you can pick the unusual out from the rest with any certainty. Of
>> course, if you live in an area with very few rocks, anything you pick up
>> might be worth investigating.
>>
>> After I have drug the magnets for a bit, I clean off anything that has
>> stuck to them into a fine mesh (window) screen sitting down in a gold
>> pan. I put water in the pan so it covers the material. I then wash the
>> materials vigorously in order to get rid of the dirt and fines, which are
>> usually magnetite. Then I screen the material again through a 1/4" mesh
>> screen. That lets me look at similar sized pieces less than 1/4" by
>> themselves, and then also those larger than 1/4" that have been separated
>> by the screen by themselves. I will keep some water in the gold pan with
>> the smaller material and do what is known in the gold panning world as a
>> blueberry bounce. That moves the heavy material to the one side of the
>> pan and lets me see any iron or metal fairly easily as otherwise those
>> pieces might remain buried under other lighter weight stones. Then I can
>> pass a strong refrigerator magnet barely above the rocks and pull out
>> almost all the bigger magnetite and iron pieces. I place the stuff that
>> that small magnet collects onto a small paper plate and examine them for
>> possible suspect stones before tossing them. (kind of like gold panning,
>> you don't want to throw out a nugget) Then I will drain and let all the
>> stones in the gold pan dry completely. Once dry, I once again do the
>> blueberry bounce technique and look over the material closely again using
>> my low-power m-scope. A hand lens, field microscope, or illuminated
>> magnifier all work but the low-power microscope has been the easiest on
>> my vision when used for any length of time. I also spend time closely
>> examining the rest of the material in the pan because stonys don't always
>> move with the heavier materials. Once I find a suspect stone, I pull it
>> out of the pan with plastic tweezers and place it on a small magnet and
>> put it under my scope for a good look. Some I recognize to be unique and
>> put them in vials for study later on, and some I keep for examples of
>> good meteorwrongs. Usually 99.999% are simply earth rocks, although even
>> some of those are quite interesting.
>>
>> Not all the suspect stones are small but most I have found are 1/2" or
>> less. A waste of time you say? Well possibly, but it has been a good
>> way for me to learn about meteorites. This hobby has helped me also get
>> interested in learning about other solar bodies as well as the earth. I
>> have a lot of folks on the Met-List to thank for most of that type
>> information. As far as meteorites go, I'm not so much into buying,
>> selling and collecting. I just really enjoy finding them myself and
>> seeing them up close.
>>
>> So again, I hope some of you who live in the "not the best place to hunt
>> meteorites" give this a try. But be extremely careful how you handle
>> strong magnets. I wouldn't want to see anyone smash a finger doing this.
>> If you are one of the young enthusiasts in this hobby, I would have to
>> recommend you don't attempt to add any magnets to the cane. Use it just
>> like it comes from the store. I did for a while and still I found some
>> very interesting stones with it.
>>
>> I have a picture here that shows both my cane and my latest attempt at a
>> magnet rake. The rake has three 80 mm square x 10 mm thick NDIB
>> supermagnets on it. If you look at it and wonder why I spaced the
>> magnets so far apart on this apparatus, suffice it to say I was too
>> chicken to get them any closer. I may move the two outside ones in about
>> an inch each at some point. I can tell you, I had a enough fun trying to
>> separate them when getting ready to put them on this rake. I wouldn't
>> want to get a body part in between two of them.
>>
>> Everything was muddy when I last used both these things. It's cold and
>> freezing here still so I haven't tried washing them off. I apologize, the
>> picture is not the best. I think if you can zoom in on the cane by the
>> wheel of the air compressor, you can still make out the 2 - 2" magnets
>> there side by side on the front edge. Don't look too close at the rake,
>> its my first attempt.
>>
>> I must explain too that my hunting method and the use of water are not
>> highly recommended by others in the world of meteorites. The magnetism
>> might affect testing the stone later on, and tap water may cause rust
>> prone stones to rust.
>>
>> Anyway, best of luck with your hunting, If you find something, share a
>> picture or two
>>
>> Mike in CO
>>
>> BTW, the last four pictures are of my first finds using my home-made
>> magnet rake. I have used it twice now on some short distance walks. I
>> believe the "suspect" iron is a match to 5 other pieces I had previously
>> found with the cane. Most likely a piece separated out of an
>> octahedrite, as I suspect the others like it that I have are. I can't
>> wait for warmer weather so I can take it out to more areas. Pictures of
>> the stones aren't too good as they are taken with a camera on the
>> m-scope.
>>
>> <http://i127.photobucket.com/albums/p124/mmurray_02/IMG_0579.jpg>
>>
>> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_i2.jpg>
>>
>> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_i1.jpg>
>>
>> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_s1.jpg>
>>
>> <http://i127.photobucket.com/albums/p124/mmurray_02/2008_s2.jpg>
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>
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