[meteorite-list] Fusion Crust on Irons was AD- Coins etc.

From: Mr EMan <mstreman53_at_meteoritecentral.com>
Date: Mon, 4 Dec 2006 16:05:30 -0800 (PST)
Message-ID: <20061205000530.25965.qmail_at_web51014.mail.yahoo.com>

I am in agreement with Martin. This is a myth that we
shouldn't allow to perpetuate on the list. An
Iron/siderite my have an original ablation surface, as
well as flow characteristics but won't have a "fusion
crust". There are many reasons I won't go into about
why iron doesn't have the composition to glass up. It
can and does develop a film of carbon and magnetite
owing to combination with atmospheric oxygen.

 I think the phrase fusion crust has been repeated so
often people have no idea what it really is. A freshly
fallen iron may have a film or veneer that you can
wipe off--but not a crust! So on this Norton and I
disagree on semantics.

As a side to all the claims of fusion crust on these
sand blasted NWA's on Ebay --"t'ain't so neither". The
glass froth we know as fusion crust is gone. Fusion
crust is easily worn away on exposed surfaces and
easily etched when in contact with the soil. What
remains is unmelted scorched matrix devoid of fusion
crust.


In the midst of this writing I see there is a healthy
debate raging on the list. I'll post now and read
later.

Elton
Received on Mon 04 Dec 2006 07:05:30 PM PST