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" <[EMAIL PROTECTED]>
To: <[email protected]>
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>
______________________________________________
http://www.meteoritecentral.com
Meteorite-list mailing list
[email protected]
http://six.pairlist.net/mailman/listinfo/meteorite-list
--No virus found in this incoming message.
Checked by AVG Free Edition.Version: 7.5.516 / Virus Database:
269.20.9/1290 - Release Date: 2008-02-20 20:45
______________________________________________
http://www.meteoritecentral.com
Meteorite-list mailing list
[email protected]
http://six.pairlist.net/mailman/listinfo/meteorite-list
______________________________________________
http://www.meteoritecentral.com
Meteorite-list mailing list
[email protected]
http://six.pairlist.net/mailman/listinfo/meteorite-list
