Dr. Ann, Dr. Ann

[Bill]

Thank You, Dr. Ann

[B.I]

ann,
i recall a conversation with david edge a few years back (quite a few) when he said the same thing. from scant memory, isnt the new/old iron down to a specific date, where iron technology changed. or, is this refering to european iron or steel which is more davids speciality. i remember him saying the date, but only remember it being around the end of the 19thC. if this branches past european, then surely this is useful information to some, whose sphere centres around the 19th/20thC

[Ann Feuerbach]

Bloomery iron and bloomery slag is different than blast furnace iron and blast furnace slag, and both differ from modern more refined steels, in elemental compostion and often in structure/phases. It is not always easy to tell them apart through microstructure or elemental compostion, but people have studied the differences with some success. I did a bit of a review in my PhD on that if you or anyone wants more details. For dates, particularly more modern ones, I'd have to look it up.
Ann

[Marc]

I think Mr. Edge could have been referring to the Bessemer Process that about the 1870's started to flood the market with cheap and almost slag-free steel. The presence or absence of slag would then be a first indicator about the authenticity of a particular object. Not definitive, but at least significative enough. Specially taken in the right context: this kind of steel was, for example, frequently used to make parts for armour in order to "complete" it, at the end of the 19th - beginning of 20th. Not necessarily with an evil intent, but after so much time it's sometimes hard to tell apart what's new-ish and what's not, so this kind of examination can help. Again, not definitive, but it's, let's say, "another tool in the box".

[Ann Feuerbach]

Yes, I agree.