[meteorite-list] NWA 969

[STARSANDSCOPES at aol.com]

Hi List,  I got permission from Johnno to  restate his email to me on the list.  He noticed a change to my Gallery and  he had some questions concerning microscopic examination of iron  meteorites.

First off,  Johnno is right, my Meteorite Times hosted  Micrograph Gallery did have some changes.   http://www.meteorite.com/meteorite-gallery/   Paul has set it up real  cool.  In the past I had Gallery posts and Micro Vision articles.  The  articles were in past issues of Meteorite Times.  Many of the articles were  material specific, that is they did not cover general microscope issues.   Those materials were not represented in the Gallery.  Paul made it so you  can (in the Gallery) scan the alphabetical menu of all material there are images  of and simply click on what you would like to see.

Second, Johnno's  observation of the Brahin Pallasite shots is correct.  That is a very close  up view of how the rust starts to attack the irons.

Third,  I have  not examined highly polished iron meteorites in incident (reflected)  light.  Has any one done this and are crystals often visible?  Perhaps  with the addition of cross polarized light?

Tom Phillips

In a  message dated 10/4/2008 4:30:41 P.M. Mountain Daylight Time, j.cabassi at ca.rr.com  writes:
G'Day Tom
Thanks for the image of NWA 969, really  incredible.  I did my normal visit to your site, you changed a few things  around, freaked me out for a minute, but then I calmed down.  A question ..  I noticed you did some photos of Brahin, being a pallasite, I can understand the  possibilities of some great images and I think I mentioned before that the lines  look identical to how rust starts to work it's way on a metal surface. But have  you tried using your techniques on just plain iron meteorites? And is there a  possibility of having microscopic crystals mixed with metal?  I just got a  12+ gram slice of Georgetown, Queensland IIICD, anomalous silicated iron. It is  a fascinating piece.

Cheers
Johnno  




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