[meteorite-list] AD: Special: An unique and truly exotic anomalous Mesosiderite - NWA 7025

From: Chladnis Heirs <news_at_meteoritecentral.com>
Date: Thu, 15 Mar 2012 22:20:06 +0100
Message-ID: <00c901cd02f1$6550cb20$2ff26160$_at_com>

Dear List community,

as it wouldn't be already a really rare event, that a new unpaired
mesosiderite can be introduced,
we have today a by all means astounding stone, worthy for one of our
Specials:

NWA 7025.

Well... if you take a look on the cut surfaces, we think, you'll tend to
guess or to reckon, to have here an evolved achondrite. Those chrystals, no
metal visible. Nevertheless not looking too weathered - Maybe a
brachinite...


To shorten it, we leave the word to the expert. Here is the gobsmacking
report of the classification:

"The specimen contains two distinct domains in contact along curvilinear
boundaries. One lithology consists predominantly of orthopyroxene with
subordinate anorthite, ~25 vol.% troilite+metal (kamacite and taenite as
small cuspate grains), accessory chromite and merrillite, and appears to be
a variety of mesosiderite. Other portions of the specimen have similar
mineralogy, except that most of the troilite and metal has been replaced by
small cuspate voids (with the same general shape as the troilite and metal
grains in the other lithology), and there is a narrow transitional zone
between these domains (see image below). The overall mineralogy and the
orthopyroxene compositions (Fs26.3-26.5Wo2.9-3.1, FeO/MnO = 26-28) are
typical for mesosiderites, and oxygen isotopic compositions determined on
acid-washed subsamples by laser fluorination at Okayama University (d17O
1.961, 1.847, 2.082; d18O 4.149, 3.992, 4.387; D17O -0.223, -0.255, -0.228
per mil) also are consistent. This specimen appears to be a mesosiderite,
which has undergone terrestrial weathering by infiltration of fluids that
selectively leached much of the primary troilite and metal in some parts of
this meteorite."


It is an anomalous, an altered mesodiderite!

Our baffling and surprising NWA 7025.


A stone for the expert.
A stone for the collector aiming for the really all new.


And now we invite you to order your specimen, as always prepared to the
standard, you're used to from Chladnis Heir's, and as long as that surprise
lasts:

http://www.chladnis-heirs.com/specials/special-nwa7025.html


Success!

Stefan & Martin

Chladni's Heirs
Munich - Berlin
Fine Meteorites for Science & Collectors

http://www.chladnis-heirs.com
Received on Thu 15 Mar 2012 05:20:06 PM PDT