[meteorite-list] old chinese meteorite coins

From: Zelimir Gabelica <Z.Gabelica_at_meteoritecentral.com>
Date: Wed Sep 14 16:41:32 2005
Message-ID: <5.0.2.1.2.20050914221819.02788b70_at_pop.univ-mulhouse.fr>

Hi Mark, Ken, Dirk, List,

Mark, you are completely right. What you say (powder and flat surface
needed, also along with other instrumental requirements and standardization
proceses) is valid for a true microprobe.
And EDX (Energy Dispersive X-Ray analysis, performed under an electronic
microscope on samples without really flat surfaces) can give you at the
best a semi quantitative results, say better a qualitative analysis (only
presence or absence of Ni and Fe K-alpha (K-beta) peaks. These can indeed
vary sustantially in intensity (thet is proportional to the amount if
X-rays emitted and thus to the amount of each metal) as a function of the
sample orientation in the beam.
The roughness of the surface is responsible of the various angles under
which the electrons reach the surface, therefore the depth at which they
penetrate the surface, this causing a large variation of the intensity of
the X-Rays emitted from the core electron shells.

In simpler words no reliable relative Ni-Fe percentages can be derived by
EDX. But a qualitative detection in this case is enough, especially if many
different areas of the coin are probed, to have a guess of the presence (or
absence) of Ni and its very approximate amount.

In other words, if I always see the K-alpha peak of Ni, for example after 5
different probings the coin surface, this will mean to me that Ni is present.
With an accurate standard (for example a flat piece of Gibeon) I could at
least very roughly evaluate the Ni % range (and of course not accurate %
value).
This would mean to me that we probably deal with a meteorite.
Of course, only then some other accurate quantitative measurements must be
done.

Yes, XRD can work as well but here indeed I am familiar with powder XRD (on
flat holders or in capillary) and this supposes destroying a small part of
the coin.

Thanks for having warned me about Taipei fakes.
My supplier was just willing to lend me the coin for analysis and envisaged
selling it only if my analysis would have strongly suggested that we deal
with a real meteorite.
  I have nothing to loose here but just expect having some exciting thrill
in trying.

Experiments are scheduled at the best for the end of next week as the
instrument is fully reserved for other analyses.

I'll keep you informed for sure. Glad to read any further comment.

All the best and good luck for the big raffle in Denver!

Zelimir


A 16:10 14/09/05 -0400, vous avez ?crit :
>Both x-ray diffraction XRD and x-ray spectometry XRF(fluorescence) will
>allow for non-destructive testing, but the operator has to understand that
>its the "relatively" flat surface that allows for this to be done, and so
>must make an equally non-destructive mount for the coin.
>I have done x-ray spectrometry on flat pieces of chert (normally, the rock
>is finely ground to a flour and mixed with something like lithium
>tetraborate and melted to form a glass disk which is then further
>flattened so that a nice flat surface is presented to be tested) which
>were placed in the holders so that as flat a surface as possible was
>presented. And, it works fairly well.
>The XRD will also work, but again, a modified holder will be needed to
>hold the coin.
>Can't wait to hear the results.
>
>Mark
>----- Original Message ----- From: "Zelimir Gabelica" <Z.Gabelica_at_uha.fr>
>To: <meteorite-list_at_meteoritecentral.com>
>Cc: <drtanuki_at_yahoo.com>; <etienne.lefebvre@skynet.be>
>Sent: Wednesday, September 14, 2005 3:27 PM
>Subject: [meteorite-list] old chinese meteorite coins
>
>
>Hello Dirk, list,
>
>Regarding old chinese coins possibly made from meteorites, here is a
>document showing one of them from the Yuan dynasty, perdiod around
>1341-1370 AD. (hope the link works).
>
>http://www.geocities.com/meteoritetaipei/well_being_a1.htm
>
>It happened that I could acquire such a coin, thus identical to the one
>pictured. Two questions arise.
>
>1) Is this coin really made from some iron meteorite?
>I will be able very soon to bring some answer by submitting the coin to a
>non destructive (EDX) analysis and check for Fe and Ni and possibly for
>other elements. The detection of only Fe (along some other metals but
>without Ni) would mean it is a fake, which, according to what is claimed in
>the text, could posibly constitute the oldest fake of an object supposedly
>being made from a meteorte.
>If the piece is really genuine (as claimed by the antiquarian seller) it
>should bear major Fe and minor Ni (say from 6 to about 20% Ni) but only
>traces (if any) of other elements (for example, the presence of Si, P,
>S...can also account for possible silicate, phosphide, sulfide...
>inclusions in the original meteoritic iron).
>And, last but not least, if only Fe and Ni are detected, this can also
>always correspond to some old artificially made coin from a (Fe,Ni) alloy
>(very unlikely though).
>I will keep you informed on the future analytical results.
>So far did someone (or Dirk) ever came across of such a coin and did
>someone analyze it ?
>
>2) In case this coin appears to be a meteorite, could someone (possibly
>Dirk, who seems to be very well documented) guess which meteoritic iron was
>used to make such a coin?
>Many old falls are indeed documented or at least vaguely mentioned in the
>old chinese literature. But possibly not such old falls.
>The coin could also stem from some old meteoritic iron find in this vast
>area. The original meteorite was perhaps also found also out of the present
>chinese borders?
>
>3) It is not impossible that the seller may get some more of such coins (I
>am crossing the fingers) so that it would be even more interesting to
>analyze several such coins and compare.
>
>Other considerations:
>
>- My coin has a typical square hole (Earth) and is rounded (Sky), as
>recently pointed out by Dirk.
>
>- My piece is moderately weathered (rust) but the ideograms can be clearly
>seen. I can make a photo, if someone interested.
>
>- The fact that this coin was not made to circulate as money but rather to
>give extra power and protection to the owner (see text in the link) could
>argue for its genuine meteoritic origin. The question here is how many of
>such coins could have been made ? Probably rather few...unless they were
>made out of a huge iron like Hoba.
>To my (poor) knowledge, the famous Armanty meteorite, the enormous IIIE 28
>tons iron found in Xinjiang and now exhibited in Urumqi (pronounce
>"urumutchi") does not show cut sides. But there are so many other potential
>meteoritic iron finds....
>
>The story is to be continued but I'd be glad to read any further comment or
>idea.
>
>All the best,
>
>Zelimir
>
>A 09:53 14/09/05 -0700, vous avez ?crit :
>>Dear List and Chris,
>>
>>Todays research results from ancient Chinese
>>literature:
>>
>>Ref: Needham, Vol.III, 20. Astronomy, pg. 434
>>
>> "Meteorites had many other names in Chinese books
>>besides the yun already mentioned, or yun-shih.
>>Further information is contained in a valuable chapter
>>by Chang Hung-Chao, who points out that one of the
>>oldest names must be that contained in the Shan Hai
>>Ching (Ch. 16), namely thien Chhuan, `hounds of
>>heaven`. He also notes that meteorites were often
>>confused (as in other civilisations) with stone axes
>>of the Neolithic period. There is a reference to this
>>in the Chiu Thang Shu (Old History of the Thang
>>Dynasty), where, about +660, a meteorite presented to
>>the emperor was called `the stone axe of the
>>thunder-god` (Lei Kung Shih Fu). Other names were
>>`the thunder-god`s ink block_at_ (lei mo) or
>>`thunder-lumps` (phi li chen), and it is these which
>>formed the headings under which Li Shen-Chen in th
>>+16th century treated meteorites in his Pen Tshao Kang
>>Mu."
>>
>>Best, Dirk Ross...Tokyo
>>
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>
>Prof. Zelimir Gabelica
>Universit? 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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Prof. Zelimir Gabelica
Universit? 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
Received on Wed 14 Sep 2005 04:44:32 PM PDT