Fistly, thank you for your time.

I'm currently trying to build a system based on the treatment some metals get in different beliefs or works of fiction, more specifically, metals. Iron, for example, is and has mostly always been the Go-To for deterring or outright nulling magical entities like Fae in Celtic myth or Druids, who can't carry many (or any) items made out of such thing for various reasons depending on the author -really, from nature, vegetarian-like abstinence to it burning them if they do, there's about everything-.

I want to take this a step further and inject some science into it. Talking from a purely material science perspective, how would different metals react to magic, should this behave similarly to radiation or thermal conduction? And if so, which ones would be best? Would purity matter as a whole, like it does for Steven Universe's Gems or Earthbenders in TLoK?

Again, thank you for your time and answers. If there's anything wrong with how this question is posed, do let me know and I'll change it as soon as possible.

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    $\begingroup$ from a purely material science perspective, how would different metals react to magic? From a material science perspective magic doesn't exist. $\endgroup$
    – L.Dutch
    Sep 27, 2022 at 15:35
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    $\begingroup$ I’m voting to close this question because it's something a book could be written about, not just an answer. $\endgroup$
    – Nepene Nep
    Sep 27, 2022 at 15:43
  • $\begingroup$ "Iron, for example, is and has mostly always been the Go-To for deterring or outright nulling magical entities like Fae in Celtic myth or Druids": no it isn't and not it hasn't. (And although quite a few classical authors speak at length about druids, not a single one of them mentions anything special about druids and iron. If the druids had trouble handling iron implements then surely Caesar, Cicero, or Diodorus Siculus would have mentioned it -- after all, the druids were powerful figures amongst the Gauls, and the Romans would have been interested to describe any weakness.) $\endgroup$
    – AlexP
    Sep 27, 2022 at 16:25
  • $\begingroup$ It's your magic system. You can have materials interact with your magic system however you want it to. Perhaps you use a strictly elemental definition of iron, and even a single iron atom will affect magic. But it's equally likely that something needs to be made of iron, for it to affect magic, permitting you to safely ignore the iron that exists in the mitochondria of plants and animals. Or iron could have no influence on magic in your world. Since literally every answer will be equally valid, this question is highly inappropriate for this site. $\endgroup$
    – sphennings
    Sep 27, 2022 at 17:16
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    $\begingroup$ Hello Facundo. Our job is to help you create and consistently use the rules of an imaginary world of your own creation - but we won't create that world for you. SE is not a discussion forum and our help center warns that we're not a place for brainstorming. Our job is to help you overcome problems you are facing in your worldbuilding efforts. What's stopping you from assigning reactions to magic? As you write a Q for here, you should ask yourself, "why do I need their help?" If you don't know, you're not ready to ask the Q. If you do now, that's the Q you should ask. $\endgroup$
    – JBH
    Sep 27, 2022 at 20:27

1 Answer 1


Magic is fundamentally controlled by magnetic fields

In order to answer this question you need to look at the properties of iron and find one thing about it that no other material available in your setting has or at least where it is a remarkable outlier. If you treat magic like radiation, then iron has a lower density than many other metal options like lead or bronze which would work better, so the radiation explanation does not work. If you are looking at magic like it is flowing electricity then iron as a semiconductor could neither be good for redirecting it as a copper alloy could nor at absorbing it out right like leather cloth. If you look at magic like flowing heat, iron has a pretty low specific heat so, you can't think of it like a thermal insulator. There is only really one property of iron that stands out in in how it interacts with any sort of know "magic like" forces, and that is its ferromagnetisms.

There are very few materials in nature that can meaningfully interact with a magnetic field. These are called ferromagnetic materials. In the pre-modern era, Iron was the only known ferromagnetic material, although cobalt, nickel, and certain rare earth metals may also make good magic resisters, they were not isolated as elements until the past few hundred years.

How you can explain it is that the world around us exists in some kind of magic scalar field that can only be manipulated by a physical being through magnetic fields. A lot of fantasy settings already have something like this: the weave, the aether, etc., but don't explain how it is manipulated. So for the sake of your setting, lets say wizards can create complex magnetic field patterns to manipulate the aether, and it is only through precise control of it that he can release its stored potential energy into a useable form.

The thing about iron is that it causes magnetic fields to change shapes; so, if a wizard is trying to make precise magnetic fields, any near by iron will change the shape of that field causing the spell to misfire.

Why does iron purity matter?

It has to due with crystalline structures. High purity carbon steels then to have crystalline structures that run in veins which are responsible for its ferromagnetic properties. However, many steels have higher concentrations of paramagnetic crystal structures like cementite and austenite that have much weaker magnetic properties. These special crystalline structures often come from "desirable contaminates" such as nickel, vanadium, molybdenum, chromium, magnesium, etc. So iron ores containing trace amounts of these metals were often recognized by blacksmiths for making higher quality steels, but they would have also been less magnetic.

In this regard you can sort of create a direct relationship between how good of a weapon/armor grade ore you have, and how good of spell resistance it will have.

  • $\begingroup$ Questions looking to brainstorm or generate ideas are not permitted on this site. As a longtime member of this site we expect you to set a good example by not answering questions with obvious issues. Sharing your opinion to a question with many valid answers, runs contrary to site policy, and the fundamental proposition of a Stack Exchange site. $\endgroup$
    – sphennings
    Sep 27, 2022 at 17:55
  • $\begingroup$ @sphennings On the contrary, the question is asking what scientific property of iron could make it uniquely effective as an anti-magic material. Of all of its properties, ferromagnetism is the only property that is unique to iron that no other materials available in a typical fantasy setting would have. Other answers are not equally valid because they would not be able to explain why a give property works for iron, but not copper, silver, wood, glass, etc. $\endgroup$
    – Nosajimiki
    Sep 27, 2022 at 18:11
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    $\begingroup$ +1. I like honest attempts to give good answers to bad questions. They may not be a perfect match for the site, but it's nice to meet them where they're at and try to help them anyway. $\endgroup$
    – Qami
    Sep 27, 2022 at 18:25
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    $\begingroup$ "In the pre-modern era, Iron was the only known ferromagnetic material": only in the sense that the original magnetic material, magnetite, is ferrimagnetic not ferromagnetic. The difference is subtle, and the entire class of ferrimagnetic materials was separated from ferromagntic materials only around the middle of the 20th century. (Fun piece of history: the original Magnetes were a Greek tribe; they founded a colony in Lydia, which they named Magnesia, after their home country. Magnetism is named after the magnesian stones found nearby.) $\endgroup$
    – AlexP
    Sep 27, 2022 at 18:30
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    $\begingroup$ @sphennings Again, I admit I misread the question and that VtC was appropriate. But if the question where more narrow like how does iron nullify magic, then it would be a very similar question to worldbuilding.stackexchange.com/questions/178310/… or worldbuilding.stackexchange.com/questions/95043/…. Just because a question can have more than one answer does not automatically mean they will all answer the question equally well. We see this a lot in questions about magic $\endgroup$
    – Nosajimiki
    Sep 27, 2022 at 21:29

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