[meteorite-list] "R" help

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Tue May 31 02:58:14 2005
Message-ID: <93aaac8905053023584aea7542_at_mail.gmail.com>

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@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,
> Universit? 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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Received on Tue 31 May 2005 02:58:12 AM PDT