[meteorite-list] Gold and Iridium content of meteorites(especiallyirons)

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Mon, 3 Oct 2011 22:13:14 -0700
Message-ID: <CABEOBjJyO8yL1PSmTWNx9n6M7D-EK0cByG6imQeWthfxu7zrzA_at_mail.gmail.com>

Hello Doug, All,
We're looking at an iron meteorite, which is a piece of material in
which predominantly heavy elements have been sorted and accumulated
through processes that took place over billions of years. Saying that
gold is uncommon in the solar system doesn't mean much; we know that
differentiation has created meteorites with upwards of 50% Ni, so
anomalous concentrations of various heavy elements don't strike me as
strange at all. NWA 859 (Taza) is a perfect example with an average
of ~2200 ppm Ge (observed range of 1500-5000 ppm).

One might as well state that it is unlikely for iron meteorites to
exist at all because hydrogen and helium make up such a large portion
of the mass in the universe/solar system:

http://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Abundance_of_elements_in_the_Universe

I'd prefer to trust the basic analytical work of one of the world's
foremost experts on iron meteorites in this case. Of course, errors
do make it into the bulletin with some regularity, often due to human
error when the data is being transferred.
If in doubt, contact the folks who manage the bulletin.
Regards,
Jason


On Mon, Oct 3, 2011 at 9:31 PM, MexicoDoug <mexicodoug at aim.com> wrote:
> 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
>
> --
> -------------------------------------------------------------------------
> --------
> 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
> -------------------------------------------------------------------------
> --------c
> 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
>>
> -------------------------------------------------------------------------
>
>> --------
>>
>>
>>
>>
>> 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
>>>>
>>
> -------------------------------------------------------------------------
>
>> --------
>>>>
>>>> ______________________________________________
>>>> Visit the Archives at
>>>> http://www.meteoritecentral.com/mailing-list-archives.html
>>>> Meteorite-list mailing list
>>>> Meteorite-list at meteoritecentral.com
>>>> http://six.pairlist.net/mailman/listinfo/meteorite-list
>>>>
>>>> ______________________________________________
>>>> Visit the Archives at
>>>> http://www.meteoritecentral.com/mailing-list-archives.html
>>>> Meteorite-list mailing list
>>>> Meteorite-list at meteoritecentral.com
>>>> http://six.pairlist.net/mailman/listinfo/meteorite-list
>>>
>>>
>> ______________________________________________
>> Visit the Archives at
>> http://www.meteoritecentral.com/mailing-list-archives.html
>> Meteorite-list mailing list
>> Meteorite-list at meteoritecentral.com
>> http://six.pairlist.net/mailman/listinfo/meteorite-list
>>
>>
>
> ______________________________________________
> Visit the Archives at
> http://www.meteoritecentral.com/mailing-list-archives.html
> Meteorite-list mailing list
> Meteorite-list at meteoritecentral.com
> http://six.pairlist.net/mailman/listinfo/meteorite-list
>
Received on Tue 04 Oct 2011 01:13:14 AM PDT