I’ve seen some stories in which “iron” counts but “steel” doesn’t, but this really doesn’t hold up. Steel is almost entirely iron and it makes no sense that mixing as little as 1% of carbon or other elements would render the iron harmless - especially as worked iron has had these “impurities” for the past 4,000 years. So what about the idea that hand-worked wrought iron is obnoxious to the Fair Folk, but not factory mass-produced metals? Or what about adopting the phrase “cold iron” as the relevant substance? That, of course, calls for a definition of what makes a particular iron “cold.”
So, what’s a fantasy author to do with all this? I still haven’t figured it out. As of now I’ve given one character iron hardware on her front door and a wrought iron coat rack in the front hall, but of course I could change that if I changed the rules of my universe. Another character wants to test for the presence of a faery, and was planning to do so with an iron object. Having reached this point I need to be very clear about exactly what sort of iron would bother the faery, and what wouldn’t. What do you think?
[Pictures: Illustration by Helen Stratton from Songs for Little People by Gale, 1896 (Image from British Library);
Di Spada e Pugnale, wood block print from Opera nova… de l’arte de l’Armi by Achille Marozzo, 1536 (Image from MDZ Digitale Bibliothek);
Two smiths making a horseshoe, wood block print by Jost Amman from Das Ständebuch, 1568 (Image from Wikimedia Commons).]