[meteorite-list] Fwd: acid for pallasite

From: Gmail <mendy.ouzillou_at_meteoritecentral.com>
Date: Wed, 21 Sep 2016 13:34:33 +0800
Message-ID: <434D4676-2FDE-45A9-9FE1-C8029BACA153_at_gmail.com>

I am forwarding for David Vann.
Begin forwarded message:

From: "Vann, David R" <drvann at sas.upenn.edu>
Date: September 21, 2016 at 11:54:44 AM GMT+8
To: Gmail <mendy.ouzillou at gmail.com>
Subject: Re: [meteorite-list] acid for pallasite

Mendy:


I am out of town using a web app that won't let me send a plaintext msg. Could you forward the following to the list? Thanks..


Re: pallasites and acid

Please do NOT use hydrochloric acid (especially hot) to dissolve the iron. It will also dissolve the olivine. If the olivine survives at all, it will be etched on the surface requiring polishing and loss of material. Phosphoric acid might be better, but it will be slow. Nitric acid is probably the best bet; it will dissolve the iron, although it wil be very slow to dissolve the nickel. . It does not have to be concentrated to dissolve the metal. This is a case where water might be your friend; the oxidation to rust results in expansion, which will pop the olivines out. Slower, but safer. My Admire specimens self-destructed this way. :( Most olivines will show shock fractures, and may be poor as gemstones (hard to facet, tending to fall apart. As curiosities, perhaps.


David R. vann, Ph.D.

Dept. Earth & Environmental science

The Unviersity of Pennsylvania


From: Meteorite-list <meteorite-list-bounces at meteoritecentral.com> on behalf of Gmail via Meteorite-list <meteorite-list at meteoritecentral.com>
Sent: Tuesday, September 20, 2016 8:54:08 PM
To: Met-List
Subject: Re: [meteorite-list] acid for pallasite
 
Francesco,

I am obviously in the minority, but I thought you wanted to keep the pallasite whole and just wanted to get rid of rust. Re-reading the email, it does seem that you may want to dissolve the iron to extract the olivines. If you want to extract the olivines, be aware that whatever acid you use will need to be very concentrated and VERY dangerous.

The risk/reward and return on investment seems hardly worth it.

Best,

Mendy Ouzillou

On Sep 20, 2016, at 11:49 PM, CRAIG MOODY via Meteorite-list <meteorite-list at meteoritecentral.com> wrote:

The very thought of it makes me cringe. The chances of getting crystals worthy of gem-stones, is slim. IMHO it would be sacrilege to destroy one of the most beautiful meteorite types, for a few gems and a little cash.

> On 09/20/16, Gmail via Meteorite-list <meteorite-list at meteoritecentral.com> wrote:
> Depending on the pallasite (is the cost of rehabilitation worth it) and the extent of rust damage, you can pursue different options. If there is rust between the olivines and iron, you will likely have to use an electrolytic process. KD Meteorites are the experts in doing this. If it is just a little bit of rust, then relish and then etch with Nital.
>
> Mendy Ouzillou
>
> On Sep 20, 2016, at 10:43 PM, Francesco Moser via Meteorite-list <meteorite-list at meteoritecentral.com> wrote:
>
> Hello!
> Wich kind of acid I can use for dissolve the iron/rust in a Pallasite, so I
> can save the Olivine?
>
>
> Thanks a lot!
>
> <x>x<x>x<x>
> Francesco
>
>
>
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Received on Wed 21 Sep 2016 01:34:33 AM PDT