Print

---

Actually, a seemingly 'characteristic' feature of these seems to be anomalous extinction...i.e., not parallel to c.  

Jim Eckert
-----------------------
At 01:56 AM 12/9/2011, Jürgen Reinhardt wrote:
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)

Please find our Email Disclaimer here-->: http://www.ukzn.ac.za/disclaimer