[meteorite-list] Admire Pallasite Destruction!

From: Sean T. Murray <stm_at_meteoritecentral.com>
Date: Mon, 19 Nov 2012 20:38:23 -0500
Message-ID: <3EA9CBE3E3C440EBAEB4C7A812BC30C2_at_PlatinumII>

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 Mon 19 Nov 2012 08:38:23 PM PST