Hi Alan, Perhaps you missed our talks at MetSoc:
https://www.hou.usra.edu/meetings/metsoc2017/pdf/6129.pdf https://www.hou.usra.edu/meetings/metsoc2017/pdf/6268.pdf NWA 11119 has more than 20% silica polymorphs (mix of tridymite and cristobalite). Best regards, Carl ************************************* Carl B. Agee President, Consortium for Materials Properties Research in Earth Sciences (COMPRES) Director, Institute of Meteoritics Professor, Earth and Planetary Sciences MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 Tel: (505) 750-7172 Fax: (505) 277-3577 Email: a...@unm.edu http://meteorite.unm.edu/people/carl_agee/ http://compres.us/about-us/compres-president On Sat, Sep 23, 2017 at 6:28 PM, ALAN RUBIN via Meteorite-list <meteorite-list@meteoritecentral.com> wrote: > A few meteorites do contain rare grains of SiO2 including tridymite, quartz > and cristobalite, but generally these grains are quite small and intergrown > with other silicate phases. Some IVA irons contain a few blades of > trydimite, but if you see a rock with several percent or more of quartz > grains that are millimeter size or larger, it will not be a meteorite. > > On Sat, Sep 23, 2017 at 4:46 PM, Abdelfattah Gharrad via Meteorite-list > <meteorite-list@meteoritecentral.com> wrote: >> >> Hello members, >> >> I really want to post my question about quartz longtimes ago, what I >> learned that if one sees quartz on a stone then the stone is not meteorite. >> in my knowledge there are different types of quartz and whose chemical >> formula is SiO2. >> >> habitually no quartz in the meteorites but if there is in a meteorite then >> it is a rare stone and whose classification differs from other meteorites >> and testimony of another planet it's just opinion. >> >> I think that the meteorites have chemical compositions like the >> terrestrial stones (magmatic, volcanic ...). the probability that a >> meteorite contains SiO2 is not zero. >> >> if there is a clarification please. >> >> Thanks, >> Abdelfattah. >> ______________________________________________ >> >> Visit our Facebook page https://www.facebook.com/meteoritecentral and the >> Archives at http://www.meteorite-list-archives.com >> Meteorite-list mailing list >> Meteorite-list@meteoritecentral.com >> https://pairlist3.pair.net/mailman/listinfo/meteorite-list > > > > > -- > Alan Rubin > Institute of Geophysics and Planetary Physics > Department of Earth, Planetary, and Space Sciences > University of California > 3845 Slichter Hall > 603 Charles Young Dr. E > Los Angeles, CA 90095-1567 > USA > > office phone: 310-825-3202 > fax: 310-206-3051 > e-mail: aeru...@ucla.edu > website: http://cosmochemists.igpp.ucla.edu/Rubin.html > > > ______________________________________________ > > Visit our Facebook page https://www.facebook.com/meteoritecentral and the > Archives at http://www.meteorite-list-archives.com > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > https://pairlist3.pair.net/mailman/listinfo/meteorite-list > ______________________________________________ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
