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RE: "akaganeite"?

Hello Alexander,

No, you are not wrong.  Debates about whether meteorites contained
indigenous chlorine raged as far back as the mid-1800s!  Iron chlorides, as
being a solid mineral phase in meteorites, was finally accepted and the name
"lawrencite" was formally introduced in 1877.  Not until 1988 did Buchwald
and Clarke's abstract make it clear that akaganeite, and not lawrencite, was
the primary corrosive culprit (see Bernd's earlier post on this subject).
Now, it's less of a debate than it is a matter of re-education.

Recently, I had a conversation with a professional meteoriticist.  When he
used the term "lawrencite disease" I interrupted him to tell him about
akaganeite and the 1988 paper.   I didn't score any points with him by doing
that, so I think that was a mistake.  He probably knew about the paper but
thought that I didn't, and may not wanted to sound too technical.
Regardless, I sent him a copy of O. Richard Norton's article, "Is Lawrencite
a Myth?", (Meteorite!, May 1999, Vol.5,No.2).  

In this article, Norton seems to make amends for perpetuating the usage of
the term "lawrencite disease" in his book (Rocks from Space), by recounting
the recent research by Roy Clarke & V. Buchwald.  Norton had the opportunity
in his article to introduce the term "akaganeite disease", but he didn't, so
I don't feel obliged to invoke it before it appears in "the literature".
When I wrote that a "rust-producing reaction was POPULARLY known as
Lawrencite Disease", I didn't mean that the term was popular with me, but
that it was a popular misconception. 

Thanks for helping in this re-education effort,
Bob V.


-----Original Message-----
From: Alexander Seidel [mailto:ase@planet-interkom.de]
Sent: Friday, November 05, 1999 1:54 PM
To: Verish, Robert S
Cc: 'Sharkkb8@aol.com'; meteorite-list@meteoritecentral.com
Subject: Re: "akaganeite"?


> To a mineralogist akaganeite is beta-FeO(OH,Cl), a member of the limonite
> family that includes goethite, lepidocrocite, and maghemite.  To a
meteorite
> collector it means the beginning of the end for an iron meteorite.
> 
> Akaganeite has been implicated of being, if not the actual culprit, then
at
> least the carrier of the chlorine ion involved in the run-away,
> rust-producing reaction popularly known as "Lawrencite Disease".

Hi Bob and List,

I realize "Lawrencite Disease" is a term from O. R. Nortonīs popular
book "Rocks from Space". But shouldnīt it rather be called "Akaganeite
Disease" for scientific accuracy? I donīt have the sources at hand, but
as far as I recall Lawrencite vs. Akaganeite has been a debate, or am I
wrong? Any specialist out there in mineralogy who can add details to
that?

> "Oh boy!  Not only do I get a Nan Tan meteorite, but I get a RARE mineral
on
> top of it - akaganeite!  Lucky me."
> He says, tongue-in-cheek,

Yeah, really sounds much more emphatically than what it plainly is:
rust!

Btw: it would be worth naming all the meteorites again here on this list
that seem to be susceptible to rust. Not only Nantan is the one, there
are other likely candidates: Lamont, Brenham, just to name two of many,
many more, though sometimes it strongly depends on the individual cuts
made.

Alex 
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