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

Sun Apr 15 12:30:09 EDT 2012

Jim,
This is square in the middle of my life as a gold exploration geo.  There is no 
fancy creative math involved with this one.  Carefully determined the volume of 
the rock.  If the matrix is primarily quartz, multiply the volume in cc by 2.65 
gm/cc to find what the rock "should" weigh without gold, giving you a baseline 
weight for the unmineralized rock.  Any additional weight is an approximation of 
the gold (+silver) content.  This obviously involves a couple of 
approximations.  If there is anything other than quartz present in the matrix 
(calcite or clays or FeOx for example), the baseline specific gravity assumption 
will have to be adjusted.  See the tektite specific gravity page on our website 
(tektitesource.com) for procedures for determination of  S.G.

Cheers,
Norm

----- Original Message ----
From: Jim Wooddell <nf114ec at npgcable.com>
To: meteorite-list at meteoritecentral.com
Sent: Sat, April 14, 2012 8:27:59 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
>f
> 
> 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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