[meteorite-list] Iron grouping/Harrison Brown/Abundance of Gold, B.W.

From: MexicoDoug <mexicodoug_at_meteoritecentral.com>
Date: Tue, 4 Oct 2011 01:19:48 -0400 (EDT)
Message-ID: <8CE506C5C7B8E39-2300-6D7A7_at_webmail-d140.sysops.aol.com>

This is a good reason to pay respects to Harrison Brown, who was an
American meteoriticist born in 1917; worked with the nuclear physicists
throughout the War and is the pioneer at the University of Chicago
along with the Anders crowd, that gift-wrapped for Leonard (and via
osmosis, Wasson) some of their most interesting fields of study.

Brown, with his grad student had no top secret responsibilities left
after the war and turned to merge his love of chemistry, work with
nuclear chemistry to ffirst apply neutron analysis to the
classification of iron meteorites and broke the ground for the
classification scheme we have today. Way back in 1949, he discussed
his results at UCLA and it caught on with the rest of the
meteoriticists.

He analyzed 45 irons of all types and found the highest gold
concentration was:

Bear Creek (Colorado, USA)
Gold content: 2.5 ug/g (yes, that's micrograms per gram i.e., ppm)
(Doug note: well below the 1490 ug/g reported in the Bulletin of NWA
6932)

So Mike - that's an oldie but goodie and addresses your question of
gold content and pretty much says it?s an error in the Bulletin you
were basing this on, without a reasonable doubt.

  Be fun to compare the values with modern analytical techniques.

Here's the reference:

http://articles.adsabs.harvard.edu//full/1949PA.....57..398L/0000399.000.html

Kindest wishes
Doug




-----Original Message-----
From: MexicoDoug <mexicodoug at aim.com>
To: meteoritemike <meteoritemike at gmail.com>
Cc: Meteorite-list <Meteorite-list at meteoritecentral.com>
Sent: Tue, Oct 4, 2011 12:32 am
Subject: Re: [meteorite-list] Gold and Iridium content of
meteorites(especiallyirons)


Hi Mike, Stuart and fellow astrochemisticists,

The Bulletin is not a peer reviewed place, it is just the world being
held on a few Atlas' shoulders who are nice enough to slave over it and
an occasional inaccuracy could happen. Perhaps it was an issue of
optical character recognition since mu, the prefix for micro (as in
micrograms) looks a lot like an m, if you put your astronomer's cap on
you'd suspect that the simple explanation it is just a run of the mill
typo that will now be corrected.

But ... since we haven't analyzed this meteorite, we can't be sure.

For my argument that it is hogwash that this meteorite would have all
that gold (so, the bigger picture is, that don't spread the idea that
there are up to 48 grams of gold in a 32 Kg chunk of iron meteorite or
folks will forget where it came from and the next thing we know the
newspapers will be proclaiming that meteorites are loaded with gold).

OK my argument, referencing Anders & Ebihara, 1982, yes the same Anders
that (karmaca) Martin kindly contacted not too long ago who invented
the term "poor man's space probe" for meteorites, showed that in the
Solar system there is nearly one hundred-million times more iron than
gold in the elemental abundances in the Solar System. Well, if an iron
meteorite has in round numbers, 900 mg/g of iron (90%), then moving the
decimal over 7 zeros, we get 0.000009 mg Au/g, which is 0.009 mg/g
which is 9 ug/g. Granted, 9 is off by a factor of 6x more than is
reported for the meteorite but at least we are not a factor of nearly
200 off (1500 ug/g = 1.5 mg/g).

That's all I can say, based on a nice guy's work from 1982... but I'm
less peer reviewed than the Bulletin so we need someone who is closer
to the analysis. Or, perhaps go through a bunch of irons with
published analyses and just see if anything is over say, 10 ug/g, in
which case that would make a far more interesting story than a footnote
to an analysis on what star made all that gold and why. Was it the
home star of Girl from the Golden Atom? Did their society get
obliterated? Did the incredible shrinking ray malfunction when
reforming their marriage ring? And what of our adventurous and
debonair young and gifted chemist? Stay tuned till next time ;-)

Kindest wishes
Doug


-----Original Message-----
From: Michael Gilmer <meteoritemike at gmail.com>
To: MexicoDoug <mexicodoug at aim.com>
Cc: Meteorite-list <Meteorite-list at meteoritecentral.com>
Sent: Mon, Oct 3, 2011 11:00 pm
Subject: Re: [meteorite-list] Gold and Iridium content of
meteorites(especiallyirons)


Hi Doug and List,

It sounded awfully high to me also, but what do I know? LOL

Quoted below is the text from the write-up. Notice, the gold content
is the only element listed in milligrams.

Here is the text from the Met Bull write-up :

Northwest Africa 6932 (NWA 6932)
(Northwest Africa)
Found: 2008
Classification: Iron meteorite (ungrouped)
History: Reportedly found in the Algerian Desert

Petrography: Plessitic octahedrite with isolated (<5% of area) sparks
and spindles of kamacite; longest bands are ~8 mm long and 0.2 mm
wide. The material may be reheated; the fine plessite has a granular
appearance and there are small dark ellipses that may reflect
resorption of phosphide. No heat altered rim was recognized. Stucture
Opl.

Geochemistry: Composition: 4.51 mg/g Co, 69.8 mg/g Ni, 82.4 ?g/g Ga,
380 ?g/g Ge, 12.0 ?g/g As, 4.12 ?g/g Ir, and 1.49 mg/g Au. The
meteorite has no close compositional relatives. For example, in the Co
range from 6.2 to 7.5 mg/g, no ungrouped iron has a Au content within
20% and only Guin and Laurens County have Ir contents within 20% of
that in this iron, but these irons differ in several other
compositional respects.

Specimens: Several additional masses are known.

Best regards,

MikeG

PS - I am having internet connectivity issues and my connection is
running about as well as a 500-pound man right now. So I think I will
sign off until tomorrow morning and hopefully it improves then. LOL

--
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On 10/3/11, MexicoDoug <mexicodoug at aim.com> wrote:
> No way Mike, that there are 48 grams of gold in that 32 Kg hunk of
tkw.
>
> ... Unless this is such an anomoly that comes from the Star of the
> Woman of the Golden Atom, I think none of this makes any sense and
that
> the units are micrograms per gram ( ?g/g ), and if that is the case
> there is not 48 grams of gold in them thar TKW, haha, more like a
total
> of 0.03 grams in the whole 32 Kg mass to go refining.  And if you read
> it somewhere, there is the possibility that the reference is wrong.
> Was the article peer reviewed?  (my comment isn't ;-))
>
> Kindest wishes
> Doug
>
>
> -----Original Message-----
> From: Michael Gilmer <meteoritemike at gmail.com>
> To: Sterling K. Webb <sterling_k_webb at sbcglobal.net>
> Cc: meteorite-list <meteorite-list at meteoritecentral.com>
> Sent: Mon, Oct 3, 2011 9:45 pm
> Subject: Re: [meteorite-list] Gold and Iridium content of
> meteorites(especiallyirons)
>
>
> Hi Gang,
>
> I was just curious about exactly how much gold is bound up inside a
> meteorite with a higher than average content, like the one in this
> example.
>
> Personally, I share the same sentiment as most of you - it would be
> heresy to destroy a meteorite to extract something that is available
> here on Earth, even if it wasn't cost-prohibitive.
>
> At 41 years old, I have made it this far in life with terrible math
> skills, so this old dog isn't going to take any refresher courses.  I
> was hoping one of the more skilled (and intelligent) members would act
> as a human calculator and cipher this question for me.  :)
>
> So in this particular case, the 32kg iron meteorite contains ~1.5 troy
> ounces of gold, with a current market value of ~$2550.
>
> What sparked my curiosity was the apparently high gold content that
> was measured in milligrams and not the usual micrograms one expects to
> see.
>
> One last question, perhaps rhetorical in a sense, has anyone ever seen
> gold in a meteorite?  I mean, has there ever been a visible "bleb" or
> gold inclusion in a meteorite?  Or is all of the gold bound up on a
> molecular level and invisible to the naked eye and 10x loupe?
>
> I guess there won't be a gold rush to the asteroid belt....
>
> Best regards,
>
> MikeG
> --
>
-------------------------------------------------------------------------
> --------
> Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
>
> Website - http://www.galactic-stone.com
> Facebook - http://tinyurl.com/42h79my
> News Feed - http://www.galactic-stone.com/rss/126516
> Twitter - http://twitter.com/galacticstone
> EOM -
http://www.encyclopedia-of-meteorites.com/collection.aspx?id=1564
>
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> --------
>
>
>
>
> On 10/3/11, Sterling K. Webb <sterling_k_webb at sbcglobal.net> wrote:
>> 1.49 mg per gram is one part in 671.
>> 1/671 of 32 kg is 47.7 grams of gold.
>> There are 31 grams per troy ounce; gold
>> is priced in troy ounces; there are 1.537
>> troy ounces oif gold in that 32 kg, or
>> $2551.94 at today's (10/03/11) price.
>>
>> Cost you more than that to extract it...
>>
>>
>> Sterling K. Webb
>>
>
-------------------------------------------------------------------------
> -
>> ----- Original Message -----
>> From: "Stuart McDaniel" <actionshooting at carolina.rr.com>
>> To: "Michael Gilmer" <meteoritemike at gmail.com>;
>> <meteorite-list at meteoritecentral.com>
>> Sent: Monday, October 03, 2011 7:57 PM
>> Subject: Re: [meteorite-list] Gold and Iridium content of
>> meteorites(especiallyirons)
>>
>>
>>> Oops, I was wrong.....It would be
>>>
>>> 32,000gr / 1.49mg = 21475 mg
>>>
>>> 21,475/1000 = 21.475 gr
>>>
>>> Right, anyone??
>>>
>>>
>>>
>>>
>>> Stuart McDaniel
>>> Lawndale, NC
>>> Secr.,
>>> Cleve. Co. Astronomical Society
>>> IMCA #9052
>>> Member - KCA, KBCA, CDUSA
>>> -----Original Message-----
>>> From: Michael Gilmer
>>> Sent: Monday, October 03, 2011 8:33 PM
>>> To: meteorite-list at meteoritecentral.com
>>> Subject: [meteorite-list] Gold and Iridium content of meteorites
>>> (especiallyirons)
>>>
>>> Hi List,
>>>
>>> In perusing through the latest additions to the Met Bulletin today,
I
>>> was reading the compositional data for NWA 6932 (iron, ungrouped).
I
>>> noticed that the gold (Au) content was listed at 1.49mg/g.  Is this
>>> sort of data as straight-forward as it appears, or is there more to
> it
>>> that this layman is missing?  In other words, how much gold is in
> this
>>> meteorite?  The TKW of this meteorite is 32kg.  So, with 1000g in a
>>> kilo, and 1000mg in a gram, how much gold is in this celestial hunk
> of
>>> iron?  (my math is horrible)
>>>
>>> Second question, what is highest known gold content in a meteorite
> and
>>> what meteorite is it?
>>>
>>> Third question, some meteorites also have high iridium content.
What
>>> is the highest known iridium content in a meteorite?
>>>
>>> I am not suggesting in any way that meteorites should be refined or
>>> melted down to extract their precious metals content, but given the
>>> high value of metals such as gold and iridium, has any profiteer
> tried
>>> such an endeavour?  Or would the process be too complex and
> expensive?
>>>
>>> Best regards,
>>>
>>> MikeG
>>>
>>>
>
-------------------------------------------------------------------------
> --------
>>> Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
>>>
>>> Website - http://www.galactic-stone.com
>>> Facebook - http://tinyurl.com/42h79my
>>> News Feed - http://www.galactic-stone.com/rss/126516
>>> Twitter - http://twitter.com/galacticstone
>>> EOM -
>>> http://www.encyclopedia-of-meteorites.com/collection.aspx?id=1564
>>>
>
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Received on Tue 04 Oct 2011 01:19:48 AM PDT


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