[meteorite-list] OT: For the Geologists and Math Wizards!

From: MexicoDoug <mexicodoug_at_meteoritecentral.com>
Date: Sat, 14 Apr 2012 12:25:10 -0400 (EDT)
Message-ID: <8CEE8724BCD09C1-8EC-ECF2_at_webmail-d018.sysops.aol.com>

Hey Jim,

Gold, huh? Break of a quarter sized piece and send it to me. I don't
return samples though because of the million I receive every day ;-)

Kidding aside, I guess there are nifty formulas floating around that
make assumptions on the matrix composition and that you've long since
figured out that your rock doesn't fi the composition assumptions. If
you have to know and that is more important than the whole specimen as
a collectible or memento, ah the meteorite conflict rears its ugly head
- I have to cut it to know what it is...

My thought would be make a nice slice right down the middle to make two
matching halves you can polish for aesthetics. Look at it for what
that tells you as to the gold aggregation in it. Maybe save the
cutting dust to check for gold content of thar. Then, check the
density of each half to see if they agree. If they don't that will be
a clue that something's up with the rock. Or you could just keep it as
is to enjoy and imagine it as you wish! Anyway good luck ;-0 -doug


-----Original Message-----
From: Jim Wooddell <nf114ec at npgcable.com>
To: meteorite-list <meteorite-list at meteoritecentral.com>
Sent: Sat, Apr 14, 2012 11:28 am
Subject: Re: [meteorite-list] OT: For the Geologists and Math Wizards!


Hi Doug and all!

Thanks for the answers.

My thought was, prior to posting the questions here, that you could not
have
a calculation that would result in a density less than the less dense
material, if the formula was correct where you have known densities of
two
specific minerals.
To add to that here, with melting or morphing or whatever, I contend
you
could not have a calculation that would result in a lower density than
any
of the known densities of any known minerals or mixtures there of.
However,
if there are unknowns, then I do see where is it very possible where it
would totally hose the results.
I stated that in another forum and then thought about it for a while
and
thought, "Oh Shxx, I had better ask people way more knowledgeable than
I".
I put the OT in the subject line cause it may or may not relate to
meteorites....I just knew some great minds are on this list.
Specifically, I have a 65g rock with a lot of gold in it. While trying
to
determine the percentage of gold in it, this particular rock is
breaking all
the rules of engagement...to the point I am about ready to take a
hammer to
it and simply do it the old fashion way with mercury....except I don't
have
any mercury! That would be the part that is totally off topic for this
list...except I found the gold when meteorite hunting! Using some of
these
wiz bang gold formulas (found on gold forums) I am coming up with
negative
numbers and one with minus 130% gold! I do not know how on earth I
could be
off by that amount using any of the areas known minerals or
combinations of.
Driving me nuts! It is such an awesome specimen, I hate to take a
hammer to
it...but two days of number crunching and testing is not "panning" out.

Jim



----- Original Message -----
From: "MexicoDoug" <mexicodoug at aim.com>
To: <clp at alumni.caltech.edu>; <meteorite-list at meteoritecentral.com>
Sent: Saturday, April 14, 2012 7:42 AM
Subject: Re: [meteorite-list] OT: For the Geologists and Math Wizards!


> Jim,
>
> In a practical sense, this is quite possible since there are more
> possibilities, where your question could be taken as too ambiguous.
> Specifics - what are you really after? I'm thinking if this relates
to
> meteorites you might have some concretions in mind as well, or
perhaps
> melting and there are rarely "just" two minerals present in nature.
When
> I mixed the concrete to fill the hole in the driveway, the hydration
(a
> chemical modification) causes a structural change as well which
> contributes to a volume change, and it was certainly more slurry than
the
> sum of the cement and sand, to adjust for the water. Some hydrations
are
> reversible and others aren't. In nature for the organized mind,
things
> usually go to hell in a handbasket since it is usually an open,
complex
> system where everything and then some goes.
>
> If you like math, some engineers probably are very concerned about
> shrinkage or expansion of concretions for the times we drive over
bridges,
> etc:
>
> maybe this gives further insight, I googled blindly:
>
http://www.byg.dtu.dk/upload/institutter/byg/nyheder/trb-06-1571-as%20submitted%20final.pdf
>
> If two minerals are melted together, it is quite possible they will
form a
> new crystal or amorphous structure, perhaps not even a clear chemical
> modification, but rather just reordering on a molecular scale that
don't
> result in voids, but do result in a new density without adding gases,
etc.
> I guess it might be a new mineral, but I'm not sure I know the
precise
> definition of a rock or mineral so I'd think of it this way.
>
> Kindest wishes
> Doug
>
>
> -----Original Message-----
> From: Chris Peterson <clp at alumni.caltech.edu>
> To: meteorite-list <meteorite-list at meteoritecentral.com>
> Sent: Sat, Apr 14, 2012 2:08 am
> Subject: Re: [meteorite-list] OT: For the Geologists and Math Wizards!
>
>
> If the two combine as some sort of conglomerate (like a breccia), and
> the combination doesn't result in voids, then the bulk density can't
be
> lower than the density of the lowest density material. But if the two
> combine chemically, resulting in an alloy or in the formation of
> different minerals, certainly the bulk density could be lower than
> either of the constituents (because you could have an increase in
volume).
>
> Chris
>
> *******************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
> On 4/13/2012 9:04 PM, Jim Wooddell wrote:
>> Hi all!
>>
>> I have a question that relates to meteorites...sort of.
>>
>>
>> If I have two minerals that are combined that have two different
>> densities, could the bulk density ever be lower the density of the
>> mineral with the lowest density?
>>
>> Examples (to make it easy) Mineral 1 = 3g/cc Mineral 2 = 15g/cc
>>
>> IOWs could I ever have a density lower than 3g/cc???
>>
>> If yes, can I please see the math?
>>
>> Thanks
>>
>> Jim
>
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Received on Sat 14 Apr 2012 12:25:10 PM PDT