[meteorite-list] Opinion - Purple in a Meteorite

[Mark Langenfeld]

Pete:

Given that you are looking into a small vug or cavity in the inclusion,
my best guess is you're looking at a thin, iridescent coating on the
face of a tiny euhedral troilite crystal.  Such purple/blue iridescence
is relatively common in terrestrial pyrites/marcasites and other sulfide
minerals.

Mark

> 
> 
> Hello, all,
> 
> I've mentioned before that my interest in meteorites is new, and have
just 
> started collecting.
> 
> I've enjoyed buying quantities of (very affordable) Unclassified NWA's
from 
> some fellow list members, then cutting, polishing, and spending hours 
> looking at them through my recently acquired stereoscope microscope. A
whole 
> new appreciation for chondrules when they're in 3-D!
> 
> Getting to the point; one stone I recently cut, and polished down to a
400 
> grit wet sand cloth, then examined through the microscope, revealed
that one 
> metallic area (troilite?) has a cavity, and in the cavity is a very
vibrant 
> purple to navy blue substance.
> 
> http://pskills.onfinite.com/album/185698/628054/
> 
> http://pskills.onfinite.com/album/185698/628055/
> 
> The only information I've turned up on the internet thus far indicates
that 
> sodium chloride in meteorites is purple and blue, but it's been found
just 
> in the matrix.
> 
> Is it more likely that this substance is some type of oxide that
formed in a 
> manner similar to a geode?
> I can't imagine salt forming or surviving inside a metallic area like
this.
> 
> I have some more close-up pics in hi-res , if required.
> 
> 
> Cheers,
> Pete
> 
> 
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