Why not do a simple test: The rutile needles are large enough to check
their extinction. They are sitting in an isotropic matrix (garnet), and
hence it doesn't matter how thick they are as long as you can see a
high-order interference colour (in an orientation roughly parallel to
the thin section plane). If the extinction is straight, it's rutile.
Titanite is monoclinic.
Ilmenite looks very different altogether.
Cheers,
Juergen
>>> Francois Guillot <[log in to unmask]> 12/8/2011 11:14
PM >>>
Hi,
I would not say no to rutile but... Raman testing of similar-looking
needles gave me titanite, once.
Let's wait for the test.
>Dear colleagues,
>
>I found a strange looking ("rhomboidal" location) inclusions in
garnet
>(Grt-Pl-Bt-Qtz-Sill metamorphic rock from the Ukraine shield). I
have
>no idea because I've never seen such a thing before. Here I'm
sending
>3 photos (thinsection, size of Grt is about 2 mm). Please
yours
>suggestions and ideas.
>
>Regards,
>Shauket
>
>IPGG RAS
>St.Petersburf
>Annexe convertie: MacintoshHD:Grt-part1.jpg (JPEG/«IC») (0015DDEE)
>Annexe convertie: MacintoshHD:Grt-part2.jpg (JPEG/«IC») (0015DDF6)
>Annexe convertie: MacintoshHD:Grt-whole.jpg (JPEG/«IC») (0015DDFD)
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