Hi Jeff, all,
The presence of Bornite inclusions in BC as
suggested by John and you, is indeed interesting.
As a mineral collector familiar with various
shades exhibited by metallic minerals, indeed
Bornite, typically bluish, is the first to come in mind.
But I also have in collection quite a few
Chalcopyrites showing a similar blue or bluish-magenta shade.
Chalcopyrite is currently brass-colored (color
similar to Pyrite, though different and thus
making Pyrite and Chalcopyrite easily discernable
from each-other only by considering their color
or glitter...) and I believe (but did not check
so far) that its blue color might indeed stem
from some "chemical restructuration" (I prefer
not to use the term "oxidation", that might be here too specific).
Indeed, when you break some (brass-colored on
surface) Chalcopyrites, you can sometimes find
such blue areas inside the fresh fracture.
I then followed your idea to Google
"Chalcopyrite" and, indeed, some of them show
blue areas or are even completely blue:
http://images.google.fr/images?hl=fr&um=1&q=chalcopyrite&sa=N&start=21&ndsp=21
Apparently the blue shade could be related to the presence of copper.
Bornite is Cu5FeS4, while Clalcopyrite is CuFeS2.
Note that Pyrite (FeS2) does not contain copper and is never blue.
I remember a few other "metallic" minerals that sometimes show blue shades.
They are (from memory): Meneghinite (Pb13 Cu Sb7
S24), Germanite (Cu26 Fe4 Ge4 S32), Briartite
(Cu2ZnGeS4) or Renierite ((Cu,Zn)11 (Ge,As)2 Fe4 S16)
(formulas just taken from the Fleitscher's
"Glossary of Mineral Species, 2008", that I always have on hand)
I don't claim that the last 4 minerals are
present in meteorites (quite unlikely) but I note
similarities with Chalcopyrite and Bornite, which are the following:
All 6 minerals involve Cu, Fe and S (S as sulfide, thus anion)
This being, Bornite and Chalcopyrite involve the simplest formulas.
Considering the Cu/Fe ratio in these 2 minerals
and the scarcity of Cu in meteorites (with
respect to Fe that is far more abundant),
obviously Bornite (that contains 5 times more Cu
than Fe) is less likely to be present in
meteorites than Chalcopyrite in which the Cu/Fe molar ration is one.
Jeff, note also that in your second link,
Chalcopyrite is more often cited than Bornite as
"terrestrially weathered iron meteorite mineral"....
These are my first speculations and hopefully
they will generate more ideas regarding this
intriguing issue (metallic-like blue spots in
meteorites, that I believe are definitely
different than the blue hibonite-containing
"chondrules" or "CAI" we discussed bout previously).
Best wishes,
Zelimir
At 10:48 11/02/2010, Jeff Kuyken wrote:
Hi all,
Thanks for everyone's input. Firstly, Robert... one of the initial thoughts
I had was exactly the same in regards to the silver streaks on Ash Creek.
Maybe it is a related type of feature.
And Mark, you're not really mistaken. Mine appears on the surface of the
trailing side of the oriented individual. I say surface and not crust
because it does look like an interior metallic inclusion which is showing
through and coloured. Gary's awesome pic of his L3 with the interior
inclusion is very much like mine but on a smaller scale. It could be quite
possible that they are one and the same thing so maybe it is a result of
oxidation and not an ablation thing.
Has there been any documentation of metallic inclusions in Buzzard Coulee?
(i.e. Fe/Ni, FeS, etc) In other falls like Bensour, this was specifically
mentioned in the classification data. It would seem there are quite a few
people who have noticed them in Buzzard stones now too.
John's suggestion of Bornite is very interesting. I had never actually heard
of it before, but it does look VERY much like that. A brilliant iridescent
blue.
http://images.google.com/images?hl=en&safe=off&q=Bornite
When I googled Bornite and meteorites, the Meteorites Knowledge Base came up
as a hit. It lists it as "terrestrially weathered iron meteorite mineral".
http://www.site.uottawa.ca:4321/meteorites/index.html#bornite
So if this is an oxidation thing as a few have suggested now, I'm wondering
if it happened on the ground or during ablation in the disturbed wake at the
back of the stone and in the bottom of an indent?
Cheers,
Jeff
----- Original Message ----- From: "Mark Bowling" <mina...@yahoo.com>
To: <meteorite-list@meteoritecentral.com>
Sent: Thursday, February 11, 2010 4:09 PM
Subject: Re: [meteorite-list] Fw: RFSPOD -
February 9,2010 Buzzard Coulee Blue Inclusion
I must have been mistaken, I thought somebody
was talking about coloration on crust and not interior features....
Mark B.
Vail, AZ
----- Original Message ----
From: Gary Fujihara <fuj...@mac.com>
To: Jeff Kuyken <i...@meteorites.com.au>
Cc: Bernd Pauli <bernd.pa...@paulinet.de>;
meteorite-list@meteoritecentral.com
Sent: Wed, February 10, 2010 7:21:54 PM
Subject: Re: [meteorite-list] Fw: RFSPOD -
February 9, 2010 Buzzard Coulee Blue Inclusion
Aloha Jeff, Bernd, et al,
I am at a conference now and have limited
access to email, but was informed of this
interesting anomalous inclusion in Jeff's
Buzzard Coulee meteorite. My friend and partner
of the NWA (~L3, W0/1) has identified a similar
feature in one of my slices. Please have a look
at my 20.11g full slice to see this blue
feature in the middle of a troilite inclusion:
http://bigkahuna-meteorites.com/Images/614g/_20.11b.jpg
Because this is from the interior of the
meteorite, it should dispel any theory of
fusion reaction during ablative flight.
gary
On Feb 9, 2010, at 11:38 PM, Jeff Kuyken wrote:
Hi Bernd & all,
Maybe it's possible but it's about 150X bigger
than my Isheyevo Hibonite-bearing CAI or
chondrule. Probably too big? Actually, I wish
you could see this feature in person Bernd.
The best way I can describe it is to say that
is looks just like the iridescent blue colour of a Peacocks feather.
I was sent a pic off list by another collector
who has a similar smaller feature on a very
fresh NWA (~L3, W0/1). There is a brassy
yellow one (troilite?) with a smaller blue one
like mine next to it. Both look like melted
metal on the surface. I know Mark had one
other much larger Buzzard with a similar thing
too. Has anyone else seen this or know what could cause it?
Cheers,
Jeff
----- Original Message ----- From: "Larry &
Twink Monrad" <larrytwinkmon...@comcast.net>
To: <meteorite-list@meteoritecentral.com>
Sent: Wednesday, February 10, 2010 11:18 AM
Subject: [meteorite-list] Fw: RFSPOD -
February 9,2010 Buzzard Coulee Blue Inclusion
Subject: RFSPOD - February 9, 2010 Buzzard Coulee Blue Inclusion
Hello Jeff K., Michael J., Zelimir and List,
I am wondering if this blue metallic inclusion in Jeff's Buzzard Coulee
might be one of these hibonites that Zelimir showed us and that Jeff
Grosman identified for us.
This made me think of the MUCH-1 and "Blue Angel" inclusions in Murchison
(both of them hibonite-bearing aggregates).
http://www.rocksfromspace.org/February_9_2010.html
Jeff, sincere congrats on such a fine Buzzard Coulee!
Best wishes,
Bernd
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Gary Fujihara
Big Kahuna Meteorites (IMCA#1693)
105 Puhili Place, Hilo, Hawai'i 96720
http://bigkahuna-meteorites.com/
http://shop.ebay.com/fujmon/m.html
(808) 640-9161
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Prof. Zelimir Gabelica
Université de Haute Alsace
ENSCMu, Lab. GSEC,
3, Rue A. Werner,
F-68093 Mulhouse Cedex, France
Tel: +33 (0)3 89 33 68 94
Fax: +33 (0)3 89 33 68 15
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