[meteorite-list] Blue Bits in NWA 1584 Chondrules

From: Walter Branch <branchw_at_meteoritecentral.com>
Date: Sat Jan 29 09:35:55 2005
Message-ID: <001a01c5060f$4b9ec6a0$6101a8c0_at_launchmodem.com>

Hi Darren and List,

Blue. Now that is interesting. I must say, I don't
recall ever seeing blue coloration in chondrites. I have
seen pink in Allende but this is a first for blue.

Thanks for sharing the pictures.

Bernd, if you wouldn't mind, would you please mail those pics
to me as well. I would like to see them.

-Walter Branch



---------------------------------------------
----- Original Message -----
From: <bernd.pauli_at_paulinet.de>
To: <Meteorite-list_at_meteoritecentral.com>
Sent: Saturday, January 29, 2005 8:14 AM
Subject: [meteorite-list] Blue Bits in NWA 1584 Chondrules


> Hello Darren and List,
>
> > I was scanning some NWA 1584 slices (one of my favorite
> > meteorites) and I noticed some iridescent-looking blue
> > areas in some of the chondrules on one of them. I looked
> > at the areas with a 20x hand lens and the blue is really
> > there, ... anyone know what is causing this effect? The
> > chondrules (if those are indeed chondrules) are around a
> > centimeter across.
>
> http://webpages.charter.net/garrison6328/bluebits1.jpg
> http://webpages.charter.net/garrison6328/bluebits2.jpg
>
> Yes, NWA 1584 is a beautiful, fresh LL5 chondrite -- this is
> true at least for the specimens the Hupes offered some time ago.
> Some other specimens that are being offered on EBay right now
> look more severely weathered.
>
> I have a very nice 10.8-gram crusted endcut from the Hupes and, here
> is what it looks like: It has a grayish matrix with several clasts and
> chondrules.
>
> There is about 60% fresh black fusion crust showing polygonal contraction
> cracks. A major feature is several large, mostly globular troilite
aggregates
> (up to 5 mm in longest dimension).
>
> I looked for those ominous, bluish areas and I found some at high
magnification
> (32x and 56x), although they are not as conspicuous as yours. To me they
have
> a bluish/violet iridescent appearance and when I slowly rotate my specimen
under
> the microscope this iridescence appears and disappears periodically.
>
> So it seems that this is (at least in my specimen) light reflected off
> mineral grains (troilite, and, well, maybe chromite or ilmenite).
>
> Darren, I'm going to attach three NWA 1584 JPEGs in separate mails to you
> so that you see what I am talking about. One of these JPEGs shows a 5 mm
> troilite inclusion (magnification 32x), #2 shows four of these violet/blue
> things (magnification 32x) and another is a wide-angle pic of my specimen
> (also showing this conspicuous 5 mm troilite inclusion at the upper left).
>
>
> Best wishes,
>
> Bernd
>
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Received on Sat 29 Jan 2005 09:32:00 AM PST