Yes Ian, I agree, it would very nice if a person such as a cosmochemist, or some other specialist in a related field should stumble across my question and be able to immediately dash off a convincing response backed up with evidence. Yes, that would indeed be all that I could ask for.
However, being a person who has spent most of his professional life asking questions and listening to the answers, I would be quite satisfied if somebody, in fact anybody, could provide a reference to something in print that went at least part of the way towards answering my question.
I have spent somewhere around 50 years trying to find that answer or part answer. I have read a lot of garbled, false and manufactured misinformation. I have read misinterpretations of genuine evidence, I have been told by academics whom I am inclined to accept do know what they are talking about, and at least in this particular matter do unquestionably know a great deal more than I do, that such differentiation of source is not possible, and in fact is an unreasonable expectation.
Nobody I have spoken with nor corresponded with, nothing I have ever read, has been able to provide a response to my question that has been able to confirm that iron-nickel material from a meteoritic source is able to be identified as such after it has been through forge processing, including forge welding.
I have come to the conclusion that all iron-nickel material found in nature and all iron-nickel from a meteoric source is in fact indistinguishable, one from the other, after it has been through high temperature processing. I am using the term "high temperature" rather than "forge", because the Luwu ores --- and others, eg, ancient Greece --- were smelted as well as forged.
Setting aside the man managed processes that material from a meteoric source and/or a terrestrial source might have been subjected to, and also the natural effects, such as those which produce the W pattern in iron-nickel meteorites, it seems to me that there is really only one indicator that will survive the forge or smelt processes that could possibly indicate that material that has been through those processes could perhaps be from a meteoritic source, and that indicator is the level of nickel content in the material.
Iron-nickel meteoritic material is characterised by nickel content that usually is between 5 to 12 percent, but can sometimes be as high as 60%.
Most terrestrial iron-nickel contains much lower percentages of nickel, usually below 2.5%.
But even this is uncertain, because in some silicate laterites the nickel content can go as high as 40%.
Then we have another problem:- some terrestrial deposits of iron-nickel are believed to be the result of ancient meteor impacts. Such a deposit is the Sudbury deposit in Canada. So in the case of such a deposit, is that meteoritic, or is it terrestrial?
I would like to hear a positive response to my question, but I doubt that I ever will. In accordance with all available evidence I firmly believe that it is a total impossibility to identify with any degree of certainty whether iron-nickel material that has been through forge (or smelt) processing is from a terrestrial source or a meteoric source.
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