[meteorite-list] Admire Pallasite Destruction!

From: MikeG <meteoritemike_at_meteoritecentral.com>
Date: Tue, 20 Nov 2012 00:36:00 -0500
Message-ID: <CAKBPJW_+f7N_cNfiy3=YiHFBSg0Xr4G2EG_Msxz=V0YnMapUag_at_mail.gmail.com>

Hi Sean and List,

Yes, us southern boys have our challenges with moisture and humidity.
I use "rechargeable" color changing dessicant cartridges in my
specimen cabinet. Presently, I keep very few specimens on open
display. 99% of my collection is crammed into one cabinet, with some
overflow in a series of vintage cigar boxes that also have dessicant
cannisters in them. I have a humidity gauge in the cabinet. I try to
keep the ambient humidity to under 30% in the cabinet. The ambient
air in the house, even with climate control, is over 60% at most
times. So I try to cut that in half inside my specimen cabinet - I
figure if I can halve the damage potential, then I'm at least making
some headway towards preserving the specimen, and not just storing it.

The cabinet is not air-tight, but many of the specimens are kept in
air-tight gemjars, membrane boxes, and the like. If I don't open the
cabinet and mess with the contents much, the humidity inside stays
lower on average. When I am packing orders or fiddling with my
collection, humid air invades my cabinet and permeates through the
drawers and specimens. There is no winning! (that is usually when
I'll go ahead and put the dessicant cartridges into the oven and dry
them out.)

After drying the dessicant, when I first put them back into the
cabinet and close up the drawers, the humidity inside will drop down
to 20% or less. I've never seen lower than 19 or 20% on my gauge.
Ideally, I'd like to see 0% humidity in the cabinet, but that is just
not easily done in a regular household in the deep south that has
kids, dogs, and constant influx of humid outside air. I'd have to
hermetically seal the cabinet or get an airtight safe or maybe have
nitrogen-purged glass cases. Again - there is no winning. ;)

I guess that is part of the reason that I don't collect many irons or
stony-irons in my personal stash. They pass through my hands from
time to time, and I enjoy them while I have them, but they are usually
temporary guests in my revolving door collection. I try to limit or
inhibit any damage these specimens might incur during they stay in my
custody, whether it is from humidity, handling (skin oils), etc.

The good news is, you can store rare bits inside sealed glass vials.
I have almost 100 sealed glass vials full of rare bits, crumbs,
fragments, etc. They stay sealed, are opened briefly to remove some
material from time to time, and the contents are never touched by my
hands in most cases - unless I drop or fumble something. For the rare
stuff or pristine material (certain achondrites, planetaries, or new
falls), I handle with white gloves. Even if I smash a small chondrite
fragment into a pile of crumbs, my bare hands rarely touch any of the
material, and I use careful methods to limit contamination. Even when
dealing with micromount crumbs, I take my custody and treatment of
them very seriously, with an eye towards preserving them as well as
making them available to collectors.

But, I digress and ramble on, back to pallasites falling apart. I've
never had it happen to me. Maybe I have been lucky. I've owned
Imilac, Brahin, Brenham, Esquel, Seymchan, Pallasovka, Admire,
Quijingue, and Fukang, and I have only had a bad experience with one
of them - it was a Brahin I bought many years ago. It was my first
pallasite specimen. It was small, it was thin, and I bought it on
eBay from a dealer who will remain unnamed. It started blooming rust
on me from the day I received it. I resold it days later, with full
disclosure, and at a loss - just to get rid of it before it completely
disintegrated on me. Unless the buyer saved it using some miracle, it
likely died in his hands. That was a lesson for me and from that day
forward, I educated myself about stony-irons and decided to be very
careful when dealing with them. And it's part of the reason I do not
collect or sell many of them......although, they sure are pretty to
look at. :)

Best regards,

MikeG

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On 11/19/12, Sean T. Murray <stm at bellsouth.net> wrote:
> I have two specimens of Admire from Keith and Dana
> (http://www.kdmeteorites.com) - one slice and one nugget - that I picked up
>
> in Tucson last year.  They have been sitting on my desk here and have held
> up extremely well.  Not a speck of rust in almost a year... and I am in
> Georgia :)  We were conducting a test to see how well Keith's preservation
> process would hold up given the humidity here in GA.  I have to say, I am
> very impressed.
>
> I'm not sure what magic he uses on the specimens, but I imagine it involves
>
> a very long contract and a signature in blood.
>
> Sean.
>
> -----Original Message-----
> From: MikeG
> Sent: Monday, November 19, 2012 6:04 PM
> To: Don Merchant
> Cc: Meteorite-list at meteoritecentral.com
> Subject: Re: [meteorite-list] Admire Pallasite Destruction!
>
> Hi Don and List,
>
> In an ideal situation, I dry specimens in the oven for at least 10-12
> hours, sometimes longer.  It depends on the specimen type and when I
> do the cutting.  If I do the cutting at noon, and the oven is not
> needed for cooking that day, I'll leave the specimens in there until
> bedtime.  If I do the cutting later in the day, they might stay in the
> oven 6-8 hours.  That is probably overkill and much longer than is
> actually needed, but I prefer to err on the side of caution.
>
> As you know, some meteorite types are more susceptible to moisture
> retention than others.  I mainly cut stones and I do not cut irons
> unless they are very small.  Mesos and pallasites are the most
> problematic - moisture likes to hide in the olivines and inclusions.
> The boundary zones between the iron matrix and the silicates/olivines
> can provide an easy route for water to penetrate deeply into the
> specimen.  It's best to just bake the living heck out of them in the
> oven to purge all moisture.
>
> For the specimens I cut, bake, and polish, I have had zero oxidation
> problems.  Admittedly, I do not cut all of my own specimens, nor do I
> prepare them all.  Some I buy from other dealers who prepared them and
> I resell them.  I try to limit my purchases to those dealers who I
> know exercise the most precautions when doing prep work - distilled
> water only, etc.  There are a few dealers that I just won't buy from,
> no matter how good the price is, because I've had rust problems in the
> past with their specimens.  Of course, less caution is needed with
> most stones, versus irons, but like Gary said earlier - some stones
> can be trouble as well, like Ghubara and Tsarev.
>
> Also, another method of contamination is wet polishing.  If a person
> chooses to wet sand, then the specimens need to be baked in the oven
> again or for longer.  Ideally, bake them after cutting but before
> polishing - this "resets" the water issue, and starts you out with a
> clean blank slate for polishing.  Then, after wet sanding, bake the
> specimen again.  Personally, I dry sand and polish.  Water never
> touches my specimens after cutting.  I dry sand by hand, in stages,
> from 100 or 200 grit, 400, 600, 800, 1000, 1200, and final buffing.
> It's a lot of work, takes many many hours, and I only do it for
> valuable specimens or specimens that demand such work.  I don't bother
> putting that kind of labor into low-cost or routine unclassified
> material - why put $20/hr worth of labor into a specimen that will
> sell for only a couple bucks a gram??  I guess I am not a
> perfectionist in that regard.
>
> I'm still learning as I go, and I am not nearly experienced with
> preparation as many people on this List.  But the methods I have
> outlined work well for me.  :)
>
> Best regards,
>
> MikeG
>
> --
> -------------------------------------------------------------
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>
>
>
>
>
>
> On 11/19/12, Don Merchant <dmerchan at rochester.rr.com> wrote:
>> Thanks List for all the great responces and opinions. Still have not
>> heard
>> from the Seller. I did ask if he cut this specimen using Tap Water
>> instead
>> of Distilled Water. Thanks for bringing up using Distilled water MikeG
>> and
>> Adam. That is all I use whenever I cut my specimens and I have never had
>> a
>> problem with a single one of my meteorites. I am not a big collector of
>> stony-irons or irons, but I do have some of these type in my collection.
>> I
>> have been very selective on purchasing these type meteorites based on
>> stability, preperation and who I purchase from. This is the only
>> meteorite
>> in all my years of collecting (Admire) that I had bad luck with. I have a
>> 300 gm. whole stone of Nantan that looks as fresh as the day I purchased
>> it
>>
>> and that was 12 years ago! So I guess I was lucky and only tossed away
>> $30.
>>
>> Again I was reluctant to purchase this from the get go, especially
>> knowing
>> the rust issues with Admire, but the Seller went to town so to speak on
>> insisting his specimens were stable. Lessons learned are like bridges
>> burned! Oh MikeG.....are you saying you heat your meteorites after
>> cutting
>> at 250 degrees for 12-16 hours! Do you mean 12-16 minutes? Seems 12-16
>> hours
>>
>> is rather overkill maybe? Just asking is all.
>> Sincerely
>> Don Merchant
>> ----- Original Message -----
>> From: "Don Merchant" <dmerchan at rochester.rr.com>
>> To: <Meteorite-list at meteoritecentral.com>
>> Cc: "Don Merchant" <dmerchan at rochester.rr.com>
>> Sent: Monday, November 19, 2012 9:28 AM
>> Subject: Admire Pallasite Destruction!
>>
>>
>>> Hi List and Happy Thanksgiving coming up to all of you. Anyways, I
>>> purchased a 6+ gm. slice of the Admire Pallasite in May of 2011 from an
>>> eBay seller with 100% feedback and of course I am not a fan of
>>> meteorites
>>>
>>> with a reputation as a Ruster! The auction by this Seller bragged about
>>> how well prepared and preserved his Admire specimens he was selling are.
>>> Well I reluctantly bought a Specimen for a $30 price tag. Well now all
>>> of
>>>
>>> you on the list can get a good laugh and view how well preserved this
>>> specimen was I purchased! I have posted this on my Website so just click
>>> the link below. If anyone else ran into this problem, contact me off
>>> list
>>>
>>> and we can email the Sellers name. I did just email the Seller on this
>>> issue and the link below to see for himself. Nothing as yet from him,
>>> but
>>>
>>> I just contacted him, so I will give it some time.
>>> http://www.ctreasurescwonders.com/admire_pallasite.html?r=20121118002710
>>>
>>> Sincerely
>>> Don Merchant
>>> Founder-Cosmic Treasures Celestial Wonders
>>> www.ctreasurescwonders.com
>>> IMCA #0960
>>
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Received on Tue 20 Nov 2012 12:36:00 AM PST