In Mistborn, allomantic powers are activated by 'burning' them, somehow using them up. But what happens to the metal after it's burnt? Does it oxidise? Is it annihilated?

I know it can't remain in its standard state and have its 'magic' used up, to use a crude term, as Kelsier mentions that Vin shouldn't leave metals unburnt as they can be toxic. If they only had their 'magic' used up, they'd remain in their normal chemical state once 'burnt'.

So what happens?

  • Metal is unmade. There is a magical reaction that unlocks some of Preservation's power, but metal is gone completely, perhaps turned into Investiture.
    – Mithoron
    Sep 14, 2023 at 20:19

3 Answers 3


I don't know that we have a canon answer to this (If there were one, it would probably come from Sanderson's web site, and I didn't see anything on there.) We can make some logical deductions, though, based on what we know.

We know:

  • Mistings can safely ingest certain types of elemental or alloy metals
  • Mistings can perform some controlled bodily function, which they call "burning", that consumes the metals and releases various types of magical energies.
  • The purity of the metals (either elemental purity or proper mixture of the alloys) is important.
    • Impure or improperly mixed metals can be ineffective or even fatal.
  • Mistings that hold "unburned" metals internally for too long risk losing them or getting metal poisoning.
  • Once the metals have been "burned", they cannot be reused or recovered.
    • This last bit is a bit of an assumption on my part, but given the scarcity of certain metals, I think if there was a "recycling" mechanism we'd have heard about it.
  • Metals that have been "burned" are not fatal.

Given all of this, the most likely explanation for what happens when metals are "burned" is some form of metabolism, similar to but distinct from digestion. It must be distinct from digestion because simply swallowing and digesting the metals results in the same poisoning as it does for "normal" people. However, the behavior of "burning" the metals has all of the hallmarks of a chemical reaction: the metals change form, release energy, and impurities in the material affect the outcome. (They must change form somehow, or else they would remain poisonous.) This could be as simple as forming some inert compound as part of the chemical reaction.

Like any other by-products of metabolism, the most natural result of this process would be for the Misting's body to extract whatever energy it could from the metals and excrete whatever's left over as waste.

Given that it's magic, of course, anything is possible; the metal may be consumed in its entirety, or it could undergo something more like fission and turn into completely different elements. But the metabolic processing seems the simplest explanation.

  • 1
    The Ars Arcanum in the Wax and Wayne series says specifically that the power does not come from the metal, rather it facilitates the power coming to the person
    – Antheloth
    Dec 3, 2018 at 20:35
  • The power doesn't come from the metal, but the metal is already infused with the power. Burning the metals also extracts this power. Jun 4, 2021 at 21:47
  • @MooingDuck Unless metal is invested, it doesn't have any power by itself, and metal being invested can be a problem, as it leads to issues concerning Identity.
    – Mithoron
    Mar 16, 2022 at 0:00

The metals burned by allomancers are consumed in order to fuel their allomantic abilities. Metal goes in, allomancy goes out; as long as you're burning allomantically pure alloys or metals, there's nothing left.

  • This is entirely untrue. If you burn chemical substance in a sealed environment it weighs slightly more due to oxidation. Wooden logs likewise oxidise, but aren't normally burnt under sealed conditions, with co2 escaping. Do you have any evidence from the series, that allomantic metals act differently?
    – AncientSwordRage
    May 8, 2012 at 6:35
  • The metal I've burnt before is magnesium in a crucible. I am less sure about non-metals, but as that's what allomancers burn it should hold true.
    – AncientSwordRage
    May 8, 2012 at 6:45
  • 1
    @Pureferret Yeah you're right, I wasn't very precise about what I meant. I'll edit the answer, but that's just an example - when an allomancer "burns" a metal, they're not literally setting it on fire in their stomach (after all, when you literally burn a metal you get heat energy out, not allomantic energy)
    – Tacroy
    May 8, 2012 at 15:49
  • My issue is your making an analogy to show that allomantic metal is completely used up, but in your example that isn't the case, whether we have a closed or open system. Do you have a outer to justify your assumption?
    – AncientSwordRage
    May 8, 2012 at 17:01
  • 2
    But where does it say in the book it's 100% used up and not turned into something inert?
    – AncientSwordRage
    May 8, 2012 at 20:28

Kelsier states that you generally should only ingest metals at the last possible moment, otherwise you end up either wasting them or poisoning yourself.

From there, we can gather that you would still be poisoned by the metals if they remained in your body after burning them, if they remain in any non-negligible amount. Since the books don't cover the poisoning, nor does the main cast seem to be poisoned, it is relatively safe to assume that not even trace amounts of the metals remain, given the behavior of Aluminium.

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