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;
http://meteorites.wustl.edu/lunar/moon_meteorites.htm
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
--
Mike Jensen
Jensen Meteorites
16730 E Ada PL
Aurora, CO 80017-3137
303-337-4361
IMCA 4264
website: www.jensenmeteorites.com
On 6/7/07, Fight Spam <[EMAIL PROTECTED]> 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
____________________________________________________________________________________
Luggage? GPS? Comic books?
Check out fitting gifts for grads at Yahoo! Search
http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz
______________________________________________
Meteorite-list mailing list
[email protected]
http://six.pairlist.net/mailman/listinfo/meteorite-list
______________________________________________
Meteorite-list mailing list
[email protected]
http://six.pairlist.net/mailman/listinfo/meteorite-list
