[meteorite-list] Hunting with a magnet; suspect stones; meteorwrongs; and ramblings.

From: Michael Murray <mmurray_at_meteoritecentral.com>
Date: Sat, 3 Feb 2007 11:11:15 -0700
Message-ID: <C9CFD4CB-7DC1-43E1-9E16-BCC49E3AFCE5_at_montrose.net>

I've been hunting meteorites with supermagnets for a little over four
years now. As I am sure everyone knows, when you drag a magnet you
pick up all sorts of stuff including a lot of magnetite, at least
here where I hunt you do. If you're interested in this type of
hunting, here is how I deal with all the metal junk, the magnetite
and the small stones. I clean the magnet off into a gold pan. I
then screen it all through a very fine screen to remove the magnetite
particles. I dump the stuff left in the screen back into the pan and
I add water with a drop of dish soap and wash. I use a swirl and
dump motion to get rid of the dirt and trash only. I usually repeat
this process with clean water at least a couple time until the water
remains fairly clean. I pass a magnet (not a supermagnet) over the
stones at about 1/2 to 3/4" above and pull out all the bits of metal
and examine them somewhat closely before getting rid of those
pieces. Don't want to inadvertently pick up a suspect stone and
through it out with the scrap. Now to have a look at all the
little stones left. I will leave just a small amount of water in the
pan with the material so that I can still swirl the contents if I
want. Then I take it outside in the sunlight and take my first
look. If I don't see anything right away that gets my attention,
I'll drain all the water off and let the contents of the pan dry
completely. Usually I just leave it sit for a day or so. So when it
is dry, I take the pan in and put it under my mscope and go through
the contents with close scrutiny. Sometimes, I have even done this
when the contents were still wet. Anyway, if I see something that
sticks out as unusual and interesting, I pick it out and take a
closer look. One quick way to separate the magnetic stones is to
place a strong magnet on the underside of the pan then swirl the
rocks for a bit over the area where the magnet is located. All the
strongly magnetic rocks will collect in one spot. Then just take the
magnet over them from above and lift them out. This lets you get
down to taking a look at the magnetic rocks in a hurry if you so
wish. I realize none of this is very scientific. It's a hobby for
me and gives me something relaxing to do in my spare time and I get
exercise from the walks. The thrill in it all comes when I actually
have something of extraterrestrial origin to look at and hold in my
hand. Then I also get a lot more enjoyment out of studying the
suspect rock to find out what it could be.

After you have been through about a five gallon bucket full of these
pea-size rocks you have a real good feel for what is a suspect
meteorite or is actually a terrestrial stone (I guess you could call
some of these meteorwrongs). I have studied the many, many, many
little "meteorwrongs" to a fairthywell. To have a good meteorwrong
to study can be a good learning tool. I have a collection of small
rocks that I keep and add to on occasion that are the best wrongs
that I have found. I look at them every once in a while under
magnification to refresh my memory on a particular feature or
whatever. I like to refer to them as "intrinsically incorrect"
compared to meteorites. Some are actually very interesting. How
about a rock that looks like chrome when you grind off a small spot
and polish it a little but it is totally not magnetic. You can't
make it leave a streak, it never rusts and is very hard. I have not
found but one piece of whatever it is and am glad to have that one to
study even though it is not a meteorite. Believe me, I have
researched this one and although I have my suspicions about it being
Hematite, I still am not positive about it.

My style of hunting takes a lot of patience but has proved that Dr.
H. H. Nininger was correct in this respect. There are a lot more
meteorites of the 3/4" or smaller than most people might suspect. I
have even found multiple pieces of the same fall doing this type of
hunting in road gravels. Twice actually. Four pieces from one fall,
two from another.

I have one hang-up however, I might talk myself into grinding a small
window into an iron but I don't think I could force myself to cut or
break a suspect stone - no matter the size. Especially improbable if
I had solid evidence to support my thinking that it was actually a
meteorite. To me the whole stone is far more of a beauty, a wonder
and marvel than bits and pieces. I know that's weird and I probably
should get over it.

Again, none of this is scientific I know, but if anyone is thinking
about hunting with a magnet, hopefully some of this information will
help you figure out a good process for dealing with what you pick
up. Good luck hunting and don't loose your patience. Don't let your
supermagnet get too close to your vehicle. If you stick it to a
painted part of the vehicle, you could really damage the paint before
you get it back off. Here is another tip...Don't use a ring type
fluorescent magnifier lamp to study the stuff in your pan. The light
intensity/reflected light, will cause you problems with your eyes,
especially when there is water in the pan. A zoom, stereo microscope
is far better to use for this reason.

Michael Murray
nom de plume - Rockbiter
Received on Sat 03 Feb 2007 01:11:15 PM PST