[meteorite-list] More on Chladnite (Was: Rocks from Space Picture of the Day - August 24, 2010) - Part 2

From: Chladnis Heirs <news_at_meteoritecentral.com>
Date: Tue, 24 Aug 2010 19:07:50 +0200
Message-ID: <003501cb43ae$e24208a0$a6c619e0$_at_com>

And because it would be unfair, to have lost that great name this way,
We have since 1994 the mineral: Chladniite

http://webmineral.com/data/Chladniite.shtml

Best!


-----Urspr?ngliche Nachricht-----
Von: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] Im Auftrag von
bernd.pauli at paulinet.de
Gesendet: Dienstag, 24. August 2010 18:57
An: Meteorite-list at meteoritecentral.com
Betreff: [meteorite-list] More on Chladnite (Was: Rocks from Space Picture
of the Day - August 24, 2010) - Part 2

BURKE J.G. (1986) Cosmic Debris, Meteorites in History, Chapter 4, p. 121:

Chladnite:

Again, it was an observation by Charles U. Shepard that paved the way toward
the
identification of the pyroxenes. In 1846 he described a mineral which, he
wrote,
"is a ter-silicate of magnesia...[and] forms more than two-thirds of the
Bishopville
stone". He named the mineral chladnite "in honor of Chladni, the scientific
founder
of this department of knowledge." Two years later Shepard reported his
analytical
results: 70 percent silicic acid, 28 percent magnesia, and 1 percent soda,
so that the
ratio of oxygen in the magnesia to that in the silica was 1 to 3. In 1851
Sartorius von
Waltershausen analyzed a fragment of the Bishopville meteorite and arrived
at about
the same results, but also found 1.5 percent alumina. Though making errors
in his
calculations, Sartorius did produce the correct formula - MgO,SiO2; however,
he
postulated that chladnite was a kind of wollastonite, in which magnesia
substituted
for lime. The issue was confused further in 1861, when Rammelsberg found by
analysis almost 3 percent alumina, 35 percent magnesia, and only 57.5
percent silicic
acid. Doubting the existence of a definite mineral, Rammelsberg did not
attempt to
devise a chemical formula.

Meanwhile, Shepard in 1854 described the Tucson iron meteorite and
speculated
that certain inclusions were chladnite. J. Lawrence Smith immediately
corrected
him, pointing out that the inclusions were actually olivine, and added a
note that
he suspected "chladnite is likely to prove a pyroxene". At about the same
time, in
1855, Gustav A. Kenngott, professor of mineralogy at Zurich, published a
memoir
giving details of the minerals of what he termed the "augite group" of the
pyroxenes.
One member of the group was enstatite, which, Kenngott wrote, was a
bisilicate of
magnesia, was "augitic in crystallization," and had the formula 3MgO,2SiO3.
In 1861, when Kenngott saw Rammelsberg's analysis of chladnite, he insisted
that
the mineral was identical with enstatite. Smith then made two analyses of
the
Bishopville meteorite and reported in 1864 that chladnite consisted of 60
percent
silica and nearly 40 percent magnesia. He agreed with Kenngott that the
mineral
was the magnesian pyroxene, enstatite, and accepted Kenngott's formula, in
which
the oxygen content of the magnesia to that of the silica was 1 to 2. Both
Rammelsberg
and Maskelyne acted to clarify the formula of enstatite, and through his
work on the
Breitenbach, Bustee, and Manegaon meteorites, Maskelyne recognized the
existence
of solid-solution series that included enstatite and bronzite. By the 1870s
mineralogists
began to report regularly these constituents in meteorites.

______________________________________________
Visit the Archives at
http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list at meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
Received on Tue 24 Aug 2010 01:07:50 PM PDT