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Re: Stupid Question?

Hi Scott and All,

In reality, the comparison of pictures of a pattern to an actual pattern in
order to identify the specimens holds little scientific weight . I assume
most of the iron meteorites found in rock shops will be either Gibeon,
Canon Diablo, or Odessa, and of these three, only the Gibeon is a fine
octahedrite. However, there are many variances in the widmanstatten pattern
even within the Gibeon locality itself.

To know the identity with a greater certainty, you would have to do a
chemical analysis and maybe even an isotopic comparison with Gibeon. Even
here, as the recent Albion discussion shows, analytic techniques may not be
enough to identify the specimen with 100 percent certainty.

The situation you are in shows the importance of keeping detailed records
of the specimens in collections. Rarely does a collection of size exist
without some unknowns.  In fact, I have encountered several institutional
collections which started out with specimens of an unknown locality.

There are many meteorite specimens for sale which are too small to show the
general nature of the overall specimen. Therefore, you could have several
specimens from the same locality and each would look much different from
the other. To carry this further, there are also many specimens that have
wandered around on the market but the locality name does not give much
information about what the specimen will look like. Impact melts, weathered
meteorites, and even Gibeons can be appear quite different. Sometimes when
two specimens of the same locality are for sale, one dealer may have gotten
a deal from another dealer and thus the lower priced specimen may not show
any of the same features or inclusions as the more expensive specimen.

One dealer on this List, Michael Casper, will sometimes provide a grade for
specimens from the same locality, and the price reflects the grade or
quality. An example of this is Sikhote-Alin. When purchasing an individual
of SA, there is a large difference between individual specimens and it is
nice to know how the specimen to be purchased compares to its siblings. The
same is true for other iron localities including Odessa, Canon Diablo,
Gibeon, Nantan, Toluca, Campo del Cielo, etc., and for stones such as Gao,
Allende, Millbillillie, and numerous other chondrites and achondrites. For
many beginning collectors, their first choice of specimen will be the
largest they can afford. Later, as their collecting tastes evolve, a
smaller specimen such as an SA individual with gorgeous features will be
much more desirable than a less-descript but considerably larger specimen
of the same locality.

As Jim Phillips has pointed out, if you can focus your collecting
strategies and desires, it is easier to make decisions about whether or not
to acquire a certain specimen. A forum  such as this List is an excellent
way to get other opinions about a specific locality and the features or
stories which will enhance the desirability of the locality.

Hope this helps,

Martin


If you can

>Hello List,
>I have been a member of the list for a couple of years and enjoy quietly
> reading and learning from some people who obviously are a lot smarter than I
> am! ... Well, most anyway..; -)
>
>But here is my question: My first meteorite was found in a local ‘Rock shop’
> in Georgetown, Colorado.  It was love at first sight and I had to have it!!
> It is a sliced and etched Fe Ni end piece.  The lady who sold it to me didn't
> know what is was or where it came from.
>
>I compared the Widmanstatten figures with images from a couple of books and it
> matches almost exactly with a Gibeon pictured.
>
>Is this a viable method of identifying meteorite specimens??
>
>Thanks for helping....
>
>Scott Maddux
>Arvada, Colorado
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