[meteorite-list] need info composition of lunar meteorites

From: Mike Jensen <meteoriteplaya_at_meteoritecentral.com>
Date: Thu, 7 Jun 2007 14:35:35 -0600
Message-ID: <6f9da8300706071335o7652cab9wcf47246ab92ed6f4_at_mail.gmail.com>

Hi Dan
First of all I would like to say welcome to the list. Hope you enjoy it here.

Unfortunately I cannot answer your question but might be able to get
you to a great website that might be able to answer your question. It
is Randy Korotev's site;

Here is some text from the site that more or less agrees with your
points about the mineral anorthite and the rock anorthosite.

"Rocks of the lunar highlands contain a high proportion (70-99%) of a
type of feldspar known as plagioclase. In particular, the plagioclase
of the lunar highlands is the calcium-rich variety known as anorthite
(the more sodium-rich varieties are rare or do not occur on the Moon).
 Mineralogically, a rock composed mostly of the anorthite is called an
anorthosite, and most rocks of the lunar highlands are, in fact,
anorthosites. Lunar scientists often refer to the highlands crust as
"feldspathic," indicating the major mineral, or "anorthositic,"
indicating the major rock type. Anorthite, like all forms of
feldspar, is rich in aluminum and poor iron."

After reading that my head is starting to swim and I'm sure I'll be
having nightmares about phase diagrams, triclinic vs monoclinic
crystals and what the hell that bar means over the second number of
the crystal indices.

If the site does not have your answer I suspect Randy will answer it
directly as he is a list member. Once again welcome to "the list".

Mike Jensen
Jensen Meteorites
16730 E Ada PL
Aurora, CO 80017-3137
IMCA 4264
website: www.jensenmeteorites.com
On 6/7/07, Fight Spam <cutspam at yahoo.com> wrote:
> Hi,
> I joined this list at the behest of someone from the
> IMCA based on concerns I have with something being
> advertised as a meteorite.  Among other errors and
> misstatements, the ad states that "Anorthosite was
> found in all the rocks returned from the Moon..."  As
> a mineralogist I find this difficult to believe.
> Anorthosite is defined as a rock type that contains
> >90% feldspar and is off-white in color, with perhaps
> a few inclusions of other minerals.  On the other
> hand, anorthite (note the subtle difference in
> spelling) is a mineral species consisting of anorthite
> feldspar, the calcic end member of the plagioclase
> series.  To make things more confusing, anorthite
> occurs as a component of anorthosite, but the two
> words mean quite different things.
> I sent two e-mails to the seller via eBay, and have
> received no response.  I would have liked to think the
> seller simply made some mistakes and listed a common
> terrestrial rock as a meteorite, but the lack of
> response gives me doubt.  However, I am also curious
> about where he might have obtained the statement with
> which I opened this note, as far as whether the
> original publication indeed says "anorthite" and that
> is simply a mistype on his part.
> Thanks,
> Dan
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Received on Thu 07 Jun 2007 04:35:35 PM PDT

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