> There is no doubt that Mohamed is a
difficult case. However, he is not a lost cause
> (realizing that you have never made such
a claim).
I
agree with you -- there's always hope. If Mohamed finds a mentor he
trusts, he
has
the potential to go far -- thanks in equal parts to his enthusiasm and
fortuitous
desert locale.
> I agree, Mohamed does not have
enough experience in recognizing real meteorites.
> But eventually he will.
It has always been my desire to shorten the time span
associated with "eventually" --
for no one's benefit but
Mohamed's.
> There were only two or three responses to
Mohameds posts which offered
> helpful information. And I was
one of them.
Yes
-- your post of January 13th was one of the constructive ones, as were
mine
from
January 7th, 12th and February 3rd. Other positive posts were made
by
Bob
King on the 13th, Allan Treiman on the 31st, and Graham
Christensen's
and
Bob Verish's also on the 31st. There were other helpful posts
(early-on)
that
I did not file. The point is people ~did~ try initially, but evidently
gave up
when
their return questions went unanswered, or their
advice went unacknowledged
and
seemingly unappreciated.
> When Mohamed says that he "knows" his
rocks are meteorites, it is clear to me that
> he is simply very hopeful.
You may be right about this. It's not always easy to tell
if someone is
being literal or not when you can't hear the words being
spoken.
> I think many people
have percieved Mohamed inaccurately, which is always
> easy when it comes to email and
foreigners. Sometimes I misunderstand Matteo.
"Sometimes?" ;-) In Matteo's case, it's clear he
doesn't speak English at
all,
but rather is using a Babel-fish-type translator. So his occasional
(frequent?)
unintelligibility is mostly the fault of the
translation software. Mohamed, in
contrast, seems to have excellent English
skills.
Mohamed: you have passion, and that by itself
can take you far. But you
must
also have trust. I honestly want you to find meteorites, and would
love
nothing better than to find ways to help you do
so. Here is a checklist that
will
help you succeed:
1. Buy a strong, rare-earth magnet. Aside
from your eyes, this is the single
most important meteorite hunting tool you can
invest in. If you can't find
any locally, or can't locate an online business
that will mail one to you,
let me know and *I* will mail one to
you.
2. Forget about metal detectors for now -- they
will only slow you down.
You
can cover much more area per unit time with your eyes.
3. If you ever have overcast days (probably
pretty rare in Oman) -- these are
EXCELLENT meteorite hunting days. The flat
lighting makes it much easier
to
detect subtle color differences (see #10 below).
4. Resolve yourself to the fact that the first
meteorite you find is almost
certainly going to be an H- or L- ordinary
chondrite. If 1 in 1000 meteorites
is a
lunar meteorite, for instance, then on average you could expect
to
find
693 other meteorites before you'd have a 50:50 chance of
finding
a
lunar -- and that assumes that all meteorites are equally
recognizable.
(A
weathered lunar or Martian meteorite is very difficult to visually
distinguish
from
common terrestrial rocks.)
5. In light of #4, purchase a small diamond
stone to "window" candidate
specimens in the field. Be sure to use
distilled water or alcohol when
windowing promising stones -- your diamond stone will
last longer,
and
any possible meteorites won't be damaged by chlorine and
other impurities found in tap
water.
6. Buy a 10x or 12x hand lens (loupe) for
examining both the exterior and
the
windowed portions of your magnetic finds while you're in the field. When
you
window an ordinary chondrite, the slurry that
develops on the surface of
the
diamond stone will be a muddy brown color. If the slurry is red
or
black, then the stone is probably hematite or
magnetite respectively.
7. Be very skeptical of any rocks you find with
gas holes in them,
especially interior gas holes that are revealed by
windowing. Also
be
quick to toss out any rocks that have solid dark interiors,
or
dark
interiors with only occasional small crystal inclusions
(called
phenocrysts). These are almost always
basalts. Your third image
down
on this link:
shows the rock interior to have the same color
as the exterior --
a
clue to its terrestrial nature.
8. Pay special attention to surface
texture. Meteorites don't tend to
have
the rough, gritty surfaces that you see in many of the
pictures
you
have posted so far.
9. Compare desert-varnished stones with
pictures of fusion-crusted
meteorites. There are differences: some
obvious, some subtle. Fusion
crusts are very thin, and often have a cracked
egg-shell look to them
due
to contraction during cooling. The fourth
picture down on this link:
is
desert varnish on what appears to be oolitic limestone. Oolites
are
not
chondrules. If you slice through one, you will see an
onion-like
interior structure which is not exhibited by
chondrules.
10. Exterior color is one of the best initial
discriminants, which is why
I
earlier recommended taking a somewhat weathered meteorite
with you
when
you go hunting. Chocolate brown or rusty brown
(the color of a
rusted tin can) is the color you're looking
for. As such, if you where
sunglasses, be careful about the
choice of color tint. I find it much
easier to recognize meteorites
without sunglasses than with them
because most have undesirable color
filtering, making it harder to
distinguish fine shades of orange, red and
brown.
There are other meteorite hunting basics, but these
are among the most
important.
Best
of luck,
Rob
