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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...... >> > >