very thin ilmenite
eric
On Dec 30, 2009, at 1:42 PM, Christian Nicollet wrote:
> Pavel Pitra a écrit :
>> Dear Eric, Andreas, Christian, Martijn and all,
>>
>> thanks for your contributions. Yes the lamellae are very thin. In
>> reflected light they are not visible with the exception of the very
>> edge (where the mineral comes to the surface) that is not more than
>> a couple of microns (or even 1µm ?) wide and has a "opaque-like"
>> reflectance.
>>
>> The pleochroisms looks real since the enclosing white micas are
>> not. I have no experience with stilpnomelane... It definitely does
>> not *look* like biotite (but could be biotite exsolution from
>> celadonitic muscovite?). Could it be very thin rutile exsolutions?
>> (from a Ti-rich phengite?; but it seems to have a much lower relief
>> than normal rutile).
>> Please pardon my ignorance, but what are "inclusions of chiller" in
>> pyroxenes?
> Oh sorry Pavel ! An old word from an old petrologist ! It's exactly
> that you have but relatively common in the cleavage of pyroxenes of
> (meta)gabbros (schiller and not chiller)
> C....
>>
>> I normally would not bother with Fe hydroxydes, but these look just
>> so conspicuous... and nice.
>>
>> Thanks a lot again!
>>
>> Pavel
>>
>> --
>>> Pavel,
>>> I would say Fe oxides, Fe hydroxides, Fe oxyhydroxides are
>>> likely. You may have more than one phase.
>>> cheers,
>>> eric
>>
>>> In a section really perpendicular to the cleavage of the mica or
>>> the cracks in the garnet , the "mineral" probably must be very
>>> thin ? I agree with Eric.
>>> It looks like the "inclusions of chiller" in pyroxenes.
>>> C......
>>
>
>
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