[meteorite-list] Flow lines on the INSIDE! Not. (cleaning irons follow-up)

From: countdeiro at earthlink.net <countdeiro_at_meteoritecentral.com>
Date: Mon, 28 Sep 2009 23:07:37 -0400 (EDT)
Message-ID: <14548618.1254193658051.JavaMail.root_at_wamui-junio.atl.sa.earthlink.net>

Hi Michael,Jason,Piper and all,

Jason here is a picture of my modest collection and that ugly Nantan with the interesting "lines" in it. I'm going to try the "reverse" electrolysis method on a 600g Campo. You can see in the pic of my cabinet a string of Campo individuals I found a few days ago in a "jewelry" store.

http://members.cox.net/countdeiro/P9250128.JPG
http://members.cox.net/countdeiro/P9280131.JPG

Best, Guido


-----Original Message-----
>From: Michael Murray <mmurray at montrose.net>
>Sent: Sep 28, 2009 8:46 PM
>To: countdeiro at earthlink.net
>Cc: Jason Utas <meteoritekid at gmail.com>, Meteorite-list <meteorite-list at meteoritecentral.com>
>Subject: Re: [meteorite-list] Flow lines on the INSIDE! Not. (cleaning irons follow-up)
>
>Hi All,
>I put my little suspect iron in a solution of water and calcium
>carbonate. I actually wrapped it loosely with tinfoil and sat that
>down in the mixture. I got out my trusty battery charger and
>connected the red lead to a sacrificial piece of junk strap metal and
>sat that down along one side of the plastic bowl. I connected the
>black lead to the tinfoil. Actually clamping it against the side of
>the bowl same as I did the piece of strap on the other side of the
>bowl. Anyway, I poured in a couple teaspoons cleanser and swished it
>around with a plastic spoon so it was dissolved good. Plugged in the
>charger and watched as a steady stream of bubbles headed from the
>tinfoil towards the sacrificial anode strap. After about two hours of
>cooking, I can now see what I have. A really sculptured, bright
>chrome something that is as hard or harder than tool steel (don't ask
>how I know that last bit) and shaped like a stretched out version of
>Willamette. I did a nickel test and think now with all I see that it
>might need to go to someone to get checked further if I want to know
>for sure. Anyway, the process worked better than I was expecting.
>Doesn't seem to be dangerous to do. I put the charger on 12V, 6 amp
>scale. I left the solution outside when it was cooking. I treated
>my specimen to a bath in penetrating oil when I had finished cleaning
>it. One more interesting tidbit, looks like after the red rust was
>removed, left on the suspect rock is a very thin black coating in
>quite a few places, mostly in the low spots. If that is magnetite
>then I answered my own question, no, the process doesn't remove the
>oxide, only the red rust. My little experiment worked well enough for
>my purposes, but hopefully no one with a stone of any value will
>follow my lead. I would hate to think I inspired someone to ruin a
>valuable specimen.
>
>Mike in CO
>
>
>
>On Sep 28, 2009, at 1:52 PM, countdeiro at earthlink.net wrote:
>
>> Hi Jason, Piper, Mike and List,
>>
>> Gathering my tattered cloak up to cover myself, I must say that even
>> I, with less than a year in the game, wouldn't be so ignorant as to
>> say I saw flow lines on the INSIDE of a specimen. What I said.. and
>> did see.. were..and I will be a bit more descriptive here...nearly
>> parallel, but sinuous, thin, rounded, iron lines orientated in one
>> direction on the outside surface of a formerly concreted and rusted
>> Nantan that I had blasted the crap out of and wirebrushed. It looks
>> lovely. Maybe I should put it eBay and call it a 100% crusted and
>> oriented individual...:o}
>>
>> Guido
>>
>> -----Original Message-----
>>> From: Jason Utas <meteoritekid at gmail.com>
>>> Sent: Sep 28, 2009 4:45 AM
>>> To: Meteorite-list <meteorite-list at meteoritecentral.com>
>>> Subject: Re: [meteorite-list] "flow lines" on weathered irons (was
>>> "question on cleaning irons")
>>>
>>> Hello Piper,
>>> Of course - hence the differential weathering rates of Campos ("old"
>>> versus "new"), to name one of many examples.
>>> Perhaps the best example of such weathering can be seen on irons from
>>> Gibeon. I unfortunately don't have a copy of Buchwald here, but if
>>> anyone does have access to the second volume, if they could flip
>>> through the Gibeon section, they would find a photograph of a
>>> beautiful mass of Gibeon (I forget the name of the mass) on display
>>> in
>>> a museum in Germany. It displays beautiful fusion crust and
>>> smooth-edged, shallow regmaglypts - it looks as fresh as many
>>> Sikhotes
>>> on the market today. Compare it to many of the larger Gibeons on
>>> ebay
>>> today and you'll see little-to-no resemblance. If anyone out there
>>> can scan a picture of said page, I'd be much obliged. It really is a
>>> good example.
>>> There are, however, a few common irons which I would never expect to
>>> have fusion crust: Canyon Diablo, Toluca, Odessa, and Nantan, to name
>>> a few. I've seen hundreds, if not thousands of examples of each, and
>>> I have never seen a single one of any of them that came close to
>>> being
>>> "fresh" enough to retain a trace of fusion crust.
>>> Nantan is one of the most corroded and least stable iron meteorites I
>>> have ever known, though Dronino's turning out to be about as bad.
>>> People need to learn more in order to clear up the misconception that
>>> all meteorites show signs of a hot, violent entry through the
>>> atmosphere; I see NWA's on ebay all the time that are nothing but old
>>> weathered fragments coated with desert varnish. Check out this
>>> seller:
>>>
>>> http://myworld.ebay.com/eegooblago/
>>>
>>> Almost all of his stones are covered in a 'glossy fusion crust.' Oh
>>> wait - those are just desert varnished fragments that have been
>>> weathered to hell. Most of the melt features the seller notes are
>>> due
>>> to sandblasting and corrosion, and s/he goes so far as to say that
>>> the
>>> cracks in his stones formed when they hit the ground! Anyone
>>> remotely
>>> familiar with meteorites and weathering processes knows that over
>>> thousands of years, meteorites fracture and break apart, in a manner
>>> completely unrelated to their having impacted the Earth.
>>> This seems like a very similar misconception; Guido even notes
>>> finding
>>> flow lines on the inside of the meteorite, having broken it open.
>>> There's no way there would have been any flow lines on the surface of
>>> the iron, never mind the inside of it. It simply isn't possible.
>>> Regards,
>>> Jason
>>>
>>> On Mon, Sep 28, 2009 at 12:47 AM, Piper R.W. Hollier
>>> <piper at xs4all.nl> wrote:
>>>> Hi Guido, Jason, Mike, and list,
>>>>
>>>> At 22:33 27-09-09, Jason wrote:
>>>>>
>>>>> Regardless of how well you cleaned your Nantan, whatever you found
>>>>> under the surface was not flow lines.
>>>>
>>>> It appears that the layers of taenite and kamacite do not always
>>>> oxidize at
>>>> the same rate at the surface of a buried iron. This would make sense
>>>> intuitively, since the proportion of nickel is different. Just as
>>>> nitol has
>>>> a differential effect on taenite and kamacite in the lab, some
>>>> conditions of
>>>> soil chemistry might produce an analogous result in the strewn
>>>> field, albeit
>>>> much more slowly. What is sometimes left after a long period of
>>>> weathering
>>>> is a pattern of parallel grooves on the outer surface that might be
>>>> (mis)interpreted as flow lines.
>>>>
>>>> This is an effect that I first noticed on a thick slice of Toluca
>>>> from Alain
>>>> Carion's collection that was on display at a wonderful exhibition
>>>> at the
>>>> Ecole des Mines in Paris in 1998. The correspondence between the
>>>> shallow
>>>> ridges on the oxidized edge of the slice and the Widmanstaetten
>>>> pattern of
>>>> the cut surface was rather obvious.
>>>>
>>>> There might be something about the specific soil chemistry at the
>>>> site that
>>>> could make this effect more pronounced at some localities (e.g.
>>>> Nantan or
>>>> Toluca) by enhancing the difference in oxidation rate.
>>>>
>>>> Piper
>>>>
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Received on Mon 28 Sep 2009 11:07:37 PM PDT