[meteorite-list] Photos of Schreibersite

From: Martin Altmann <Altmann_at_meteoritecentral.com>
Date: Tue Feb 8 09:48:33 2005
Message-ID: <003801c50ded$a0559260$045f9a54_at_9y6y40j>

Hi list,

better than to stay in remembrance only because of silly comments,
I should share some educational pictures of schreibersite.
Loaded up some photos with all the features, rhabdites, ribbons, planes,
large crystals.
Unfortunately in that yahoo-thing, the pictures are displayed somewhat
small. Just load them down and make them larger on your screen.

http://de.pg.photos.yahoo.com/ph/metmartinde/my_photos

They are numbered in that order like in the description down here.
(Soon I'll be able to make better pictures, I have the Nikon 4800 yipiieh).

Any remarks or better, some more pictures?
Cheers
Martin
.....
Hi Jeff,

in the first picture, you have a microscopic view of those tiny
Rhabdite-crystals (in Morasko).

in the second picture you have a Sikhote-Alin, showing both: All the tiny
light spots are those rhabdites! and the large, here greyish reflecting
inclusion is schreibersite as a large crystal.

In the Odessa picture, I hope you can read the somewhat tiny scripts,
there you have down on the bottom a schreibersite inclusion rimmed with
cohenite! The schreibersite in that picture looks a little bit more shiny
and more silvery than the cohenite, note the many cohenite worms in the
slice, often parallely oriented to the Widmannst?tter pattern.

Finally again the Morasko, you already know.
Again cohenite wormlets in the upper half, but look at the large
troilite-graphite-inclusions.
Brownish (more golden in natura) is the troilite, combined with blackish
graphite and
surrounded by a thin rim of schreibersite (bright silver) and on the
outside, darker in the picture, cohenite.
The troilite-eye in the middle has only schreibersite and cohenite around,
the incomplete troilite on the right edge has again all three.

Here another Morasko with a closer view on a troilite eye:
Here we have an incomplete ring of graphite to the right (black),
a complete fancy rim of schreibersite (silver)
and last but not least a rim of cohenite (grey).

Here the total view of that slice. Extremely much cohenite, parallely to the
Widmannst?tter, note the strong Neumann lines in some kamacite fields.

What a beauty. But Jeff, I tell you, meanwhile here in Germany it makes no
sense to offer such jewels. Most collectors don't appreciate such
extraordinnary specimens, where all exotic features are displayed together
in one single piece, thus where you have to cut a lot of Moraskos to find
all the features together and where the preparation is so brilliant (all
grinding and polishing done by hand). They see on ebay ending trashy rough
specimens of Morasko at 0,6$ or in recent time the non-etched slices without
any inclusions and than they rant, that I would be crazy, if I ask 2 or
2.5/gram for such museum pieces (in fact the irons in museums here are often
very rotten. In Berlin they have now a funny idea for raising funds for
restoring the irons. You can "adopt" a specimen, paying a sum for
restoration and you will be invited on one day to visit the restauration
process).

Now to schreibersite in planes. I can't find the picture anymore, but go to
David Weir's site and choose IIG, Guanaco.
http://www.geocities.com/~dweir/
Oops, it doesn't work at the moment, but from my memory the slice had large
schreibersite like in the Sikhote picture but also schreibersite ribbons or
planes crossing the whole specimen. In the picture, was a direct scan, they
are visible in straight dark lines or clefts. Thats a reason, why one can't
cut large thin slices of Guanaco, it will fall in pieces along this
rhabdite-planes.

Finally a funny feature of schreibersite in the Fredericksburg hexahedrite:
First it is sparkling (picture FB39,84C) here along diagonal ribbons,
second you find it too in form of little "arabic letters" along this planes.
(picture FB39,84D).
Only to complete, of course it has great Neumann lines too. (picture ...Ab).
Something else, than the splattered slices in US-ebay, isn't it?

All specimens here were prepared by the Iron God himself: Pilski and are
sold, but if you like to have such fine specimens (and I made lousy photos)
for your collection, I could offer you from time to time smth like this.
Received on Tue 08 Feb 2005 09:51:09 AM PST