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, [EMAIL PROTECTED] <[EMAIL PROTECTED]> 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, > [EMAIL PROTECTED] 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" <[EMAIL PROTECTED]> > To: "met list" <[email protected]> > 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 <>< > > ______________________________________________ > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
