[meteorite-list] Fusion Crust on Irons--Not

[debfred at att.net]

  Carl, I need some help here. Which one of these elements or minerals is in the silicate group? 
Sikhote-Alin is a coarse iron octahedrite. Its composition is as follows: 5.9% nickel, 0.42 % cobalt, 0.46% phosphorus, 0.28% sulfur, smaller amounts of germanium and iridium, and the remainder (approximately 93%) is iron. The following minerals are present: taenite, plessite, rhabites, troilite, chromite, kamacite, and schreibersite crystals. ... 
Regards, Fred
-------------- Original message ----------------------
From: <cdtucson at cox.net>
>
If I'm not mistaken. The crust shown on Sikhotes may well be a true fusion crust 
> because sikhote does contain some silicate minerals  within it.
It is the irons without silicates that cannot produce a true fusion crust. And 
as Elton said, Nobody has ever shown one of these non-silicate irons with fusion 
crust. In fact the two examples shown are the only examples I have ever seen of 
any type of iron meteorite with fusion crust, not counting true silicated irons 
> of course. 
Does anyone have other pictures of any irons with fusion crusts to share? Thanks 
> Carl
> --
> Carl or Debbie Esparza
> Meteoritemax
> 
> 
> ---- ensoramanda at ntlworld.com wrote: 
> > Hi Elton,
> > 
> I think it is that thin coating of magnetite that most folks are calling a 
> fusion crust on fresh irons...what else can it be called?
> > 
> As you say, unfortunately it is quite fragile and on most irons it flakes or 
comes off after very little time in our climate, so most of those wonderful 
> looking sikhote alins at the shows have actually been cleaned and treated and 
> have lost the magnetite 'fusion crust'. I have seen many with remnants which you 
> can see still peeling off but rarely in their pristine matt grey original state. 
> Also, as you say, those flow lines can be still present mostly underneath when 
> the magnetite/crust has gone but are I think much more detailed and sharp when 
> the magnetite coating is fresh.
> > 
> > If you know of a different name/term to call the magnetite coating on fresh 
> irons other than fusion crust then I am sure we would all like to know what we 
> should call it?
> > 
> > Regards,
> > 
> > Graham
> > 
> > 
> > 
> > ---- MEM <mstreman53 at yahoo.com> wrote: 
> > > Stopping in a few minutes to state again that all this discussion about 
> fusion crust on irons is right next to unicorns postulations.  Everyone says 
> that fusion crust on irons exists but no one can come up with the proof. 
> Non-silicate bearing irons DO NOT/CANNOT have FUSION crust: they have a very 
> fragile magentite micro-crystal "film" and they have an ablation surface but, 
> they can't by definition have a "fusion crust" and no matter whom the expert 
> quoted they still do not have a fusion crust. A fusion crust has to have a 
> silicate source to for the glass component of the crust--  Nada, Nix, No How.  
> > > 
> > > Both silicate and non-silicate meteorites have an ablated/ablation surface, 
> and they can show flight features--but not all meteorites have a fusion crust.  
> I have some OCs which have flow lines UNDER the fusion crust remnants.
> > > 
> > > If anyone still defends the presence of fusion crust on (non-silicate 
> bearing) irons then show me the "crust"...can't?..ok show me the glass? ....  
> right then-- no photos, no thin sections, no micro graphs???......And while 
> there was one close up of an ablated surface showing soft wavy lines of briefly 
> melted metal that was aligned to aerodynamic vectors--This does not fusion crust 
> make.
> > > 
> > > Unlike in politics and public opinion, in science, no matter how often an 
> untruth is repeated it doesn't become "truth" by majority belief. But science, 
> being a human endeavor, sometimes can find itself "off track" and when it does 
> it accepts the error and gets back on track.
> > > 
> > > Elton
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