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

From: Norm Lehrman <nlehrman_at_meteoritecentral.com>
Date: Sat, 3 Feb 2007 22:27:03 -0800 (PST)
Message-ID: <20070204062703.71223.qmail_at_web81013.mail.mud.yahoo.com>

Rockbiter & list,

I enjoyed your write-up. I've always viewed the
magnet as a tool to test things seen by the eye
rather than a collecting tool, but you've made your
point well.

Recently en route to Tucson, I spent a day in the
Arizona desert. There are rainwater collection and
dispensing systems out there for wildlife
("guzzlers"), and these include large concrete aprons
to collect the rain. In one of these I noted a few
gallons of particulates collected in a sediment trap
at the bottom, so I ran a magnet through this
material. In this magnetic fraction were dozens of
tiny metallic to glassy spheres. It seemed to good to
be true. While it WAS what I was hoping to see, it
was just too easy. There had been some welding in the
area building tanks and fences, so I'm concerned that
some or all of these sphereoids might be particulates
from the welding. Have you found such things away from
civilization?

Secondly, you said:

" 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."

For sure it is not hematite. Hematite has the most
distinctive streak in the mineral kingdom (rusty
vermillion red even when the hematite is bright and
metallic as a silver mirror). I am confused how you
collected it with a magnet if it is absolutely not
attracted to a magnet. Whatever the case, there are
lots of hard, silver minerals not attracted to a
magnet, A good bet would be ilmenite.

Cheers,
Norm http://TektiteSource.com


--- Michael Murray <mmurray at montrose.net> wrote:

> 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
>
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Received on Sun 04 Feb 2007 01:27:03 AM PST