[meteorite-list] Use of magnets for meteorite hunting

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Thu Apr 22 10:23:44 2004
Message-ID: <AF564D2B9D91D411B9FE00508BF1C86901B4E77C_at_US-Torrance.mail.saic.com>

Hi Pierre and List,

Here's my take on the use of magnets to search for meteorites.
If you're a novice meteorite hunter -- by all means use them!
Hobbling a beginner by removing this basic tool from his
arsenal is unfair, unrealistic, and completely unnecessary.
It's hard enough making that first find -- doing so without
a magnet will just make it take that much longer.

As for disturbing the latent magnetic field of some ordinary
chondrite, the reality is that no one is ever going to spend
the money to measure it for your meteorite. No one. The
evidence? There are hundreds of thousands if not millions of
recovered meteorites in the world's collections today. On a
percentage basis, what fraction of those were found without
the use of a magnet (well over 95%) and what fraction of those
have been analyzed magnetically (less than 0.1%)? The point
I'm trying to make is that anyone really interested in the
latent magnetic fields of meteorites has far more material
already at their disposal than they could ever have time or
money to test.

That said, I do not believe a magnet is especially useful
to a veteran meteorite hunter (who isn't searching a known
strewnfield). Indeed, as Pierre and others have argued,
dependence on a positive magnet response may eliminate
some of the rarer and more scientifically valuable
specimens. I still carry one with me, but I rarely use
it any longer. My eyes are a better discriminator.

So to me it really boils down to a non-issue. When meteorite
hunters are first starting out, they'll use a magnet until
they have a few dozen ordinary chondrite finds. Sure, they'll
magnetically "kill" these finds, but their mounting success
will eventually wean them from their magnets at about the
time that over-dependence on them would hurt hunters more
than help them. --Rob

P.S. Perhaps a compass can be used as a "weaning" device?
It generates a minimal magnetic field, and yet is sensitive
enough to detect most H- and L-chondrites.
Received on Tue 04 Mar 2003 01:41:37 PM PST