[meteorite-list] "R" help

Tue May 31 02:58:12 EDT 2005

Hello All,
R-chondrites contain a very small amount of metal and/or magnetism. 
Although a very slight pull is detectable with the very strongest
rare-earth magnet, most will not give any pull at all.  However, Rob
(Wesel) was correct in saying that NWA 801 is [very] highly magnetic. 
This is because NWA 801 is a CR chondrite, not an R chondrite (and CR
chondrites tend to contain a good deal of free metal and armoured
chondrules).  I'm not sure about most R-chondrites, but NWA 753 (R3.8
I believe) does seem to contain a good deal of what appears to be
numerous fine particles of iron sulfides dispersed throughout the
matrix -- does anyone else have any slice(s) that show this?
Regards,
Jason

On 5/30/05, MexicoDoug at aol.com <MexicoDoug at aol.com> wrote:
> Rumuruti's are expected to be weakly magnetic/possibly magnetized.
> Pyrrhotite is usually weakly magnetic, and 5% is going to be really weakly  magnetic
> though I expect it will now deflect a compass needle...but if you look  at the
> composition of Rumuruti's you can learn a lot.
> 
> Oh no Tom don't be hard on Martin just because David Weir only anticipated
> 999 out of 1000 of our silly questions!!!  My lazy take on this stone made
> famous by Mike Farmer since as he aptly put it, "they stink like sulfur when he
> cuts them" (Mike's descriptions rival those fabled David New Deals).  That  is
> actually a pretty important comment, since it is that slightly iron
> difficient Iron Sulfide known as pyrrhotite that apparently is the main magnetic
> component of Rumuruti chondrites, which Mike did/does have an awesome specimen  in
> his collection.  Pyrrhotite is what does smell like rotten eggs when
> attacked by nibbling meteoritehounds...
> 
> That Iron Sulfide in the Rumuruti  Chondrites is found, at least according to
> the excellent team at  Mineralogisch-Petrographisches Institut and Museum,
> Germany &  Max-Planck-Institut fuer Chemie, Germany, in the form of pyrrhotite
> and is the  main magnetic mineral of Rumuruti was tested.  These ace
> researchers went  on to quantify that Rumuruti itself is composed of 4.4 volume percent
> pyrrhotite.  Mind you, that is probably 5% by weight considering its higher
> denisity.
> 
> Meteoritics V. 29, No. 2, pp. 275-286 March 1994
> "Mineralogy  and Chemistry of Rumuruti: The First Meteorite Fall of the New R
> Chondrite  Group" by Schulze, H.; Bischoff, A.; Palme, H.; Spettel, B.;
> Dreibus, G.; Otto,  J.
> 
> Now, on to your question regarding how magnetic.  Well do you  mean magnetic
> in a Dave Freeman sense?  Because, yes, now that you have  ignited Ramona
> Geraldine Quimby (Beezus's little sister)'s curiosity under the  whole meteorite
> world sticking rare earth magnets powered by the dark side of  the force,
> everybody's Rumuruti's are probably magnetized to saturation.   They can test to
> see if the Rumuruti's pick up iron filings now - and some may  truly have
> magnetized meteorites, and in the process have lost scientific value  just like
> putting one of those bad-ass magnets on specimens from a new cassette  tape
> collection to see if they are magnetic (well, are they?).  The funny  thing is they
> were probably weakly magnetized extraterrestrially  before.
> 
> Furthermore, the Pope's, France's and Italy's team comment on the  magnetic
> profile of the Rumuruti's, we can learn from harvesting Google, that  the
> Rumuruti exhibits minimal magnetic anisotropy.  That means God's  original
> recording of preferential magnetization axes recorded somehow in  outerspace since the
> mineral pyrrhotite does orient magnetically should happen,  but it became
> unoriented afterwards.  Note unoriented and oriented are  terms for magnetization
> anisotropy here and not flight markings.  This is  noted by these noble
> researchers and explained that they were probably  "recrystalized" after the
> original formation.  I guess they are suggestion  that the pyrrhotite was heated
> above 350 degrees C which ought to do the  trick.  Unless you take a powerful
> enough magnet and try to reorient it  depending on where you stick the magnet...
> 
> It is important to know if you  are dealing with an isotropic magnetic
> material or not when you ask questions  like how magnetic - as results can really
> depend on the orientation of the stone  and if you don't know this you can get
> pooh pooh out of the test if not  careful...
> 
> Lunar and Planetary Science XXXVI (2005)
> AN IMPACT ORIGIN  FOR THE FOLIATION OF ORDINARY CHONDRITES.
> J. Gattacceca1, P. Rochette, M.  Denise, G. Consolmagno, and L. Folco,
> Université Aix-Marseille III, CEREGE,  BP80, 13545 Aixen-Provence, France, MNHN,
> Paris, France, Specola Vaticana,  Vatican City State, Museo Nazionale Antartide,
> Siena, Italy.
> 
> Finally, the  fact that pyrrhotite is magnetic (magnetized) should come as no
> surprise.   Martian meteorites especially suspected of being from certain
> regions of Mars  contain this mineral, and as a matter of fact Mars (Geo)ologists
> have speculated  that certain less magnetic areas on the Martian surface were
> unoriented as a  result of impacts, etc...  That's another good reason npot
> to &#(*#  with the magnetization of your Mars rocks.  That tidbit of
> information in  the magnetism just might tell you what part of a planet your rock is
> from.   Or for that matter what part of the Rumuruti parent body...
> 
> Saludos,  Doug
> 
> ==================
> En un mensaje con fecha 05/30/2005 6:29:53 PM Mexico Daylight Time,
> Altmann at Meteorite-Martin.de escribe:
> But Tom!
> 
> I won't tell the  solution.
> Try David Weir's Studies!    http://www.geocities.com/CapeCanaveral/9278/
> It is always the first place to  look for answers for questions like yours
> now. Simply the best place on  web
> and I bed in this respect better than your  books.
> 
> Buckleboo!
> Martin
> 
> ----- Original Message -----
> From:  "Tom Knudson" <peregrineflier at npgcable.com>
> To: "met list"  <meteorite-list at meteoritecentral.com>
> Sent: Tuesday, May 31, 2005 12:54  AM
> Subject: [meteorite-list] "R" help
> 
> 
> > Hello List, the list  sure is slow, must mean that some people have lives!
> > Anyways, I searched  the internet and my book and can not find an answer to
> > this  question.
> >   Do "R" chondrites have any metal?  It seems  like the have a tiny bit,
> but
> > not enough to be visible. Are they  attracted to a magnet at all?
> > Thanks, Tom
> > peregrineflier  <><
> 
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