[meteorite-list] Re: NaOH de-rusting solution and sulfide inclusions

From: Steve Schoner <steve_schoner_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:21 2004
Message-ID: <20031003174827.17575.qmail_at_web12704.mail.yahoo.com>

--- Steve Schoner <steve_schoner_at_yahoo.com> wrote:
> In NaOH treating of certain irons such as Uruacu and
> certain sulphide rich irons I have noticed that the
> inclusions become gold to brown. It is a very nice
> effect on irons that have already been etched, where
> these incluions are not so affected by acid etching.
>
> The change is superficial, and does not penetrate
> beyond the immediate surface.
>
> It really brings the detail out and makes these
> stand
> out against the previously acid etched surface.
>
> Steve Schoner/ams
>
> P.S. As soon as I get the Uruacu out of solution, I
> will snap a photo to show the effect.


I could not wait, I snapped these photos while the
specimen was still in solution.

The photos show the gold color and the effect on the
sulfide inclusions.

But actually looking at the specimen, the gold is
spectacualar, like solid gold against the iron. And
the troilite is dark brown like a deep bronze, darker
than just as it was in etched specimens alone.

The acid etched iron shows no adverse effects from
NaOH at all.


Overall photo of specimen showing golden carbibe and
sulfide inclusions, expecially along the top edge.
But this picture does not show the specimen very well,
as the coloration is spread evenly over all the
inclusions.

Photo 1

http://www.geocities.com/american_meteorite_survey/Uru1.jpg



This photo is a closeup, and shows the color changes
very well, but still not as nicely as it would be if
you actually saw the specimen in hand.

Photo 2

http://www.geocities.com/american_meteorite_survey/Uru2.jpg


Steve Schoner/ams

 

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Received on Fri 03 Oct 2003 01:48:27 PM PDT