In the latest of the American Chemical Society's Reaction videos, cosplayer and science geek Ryan Consell dives into the chemistry behind Valyrian steel, a rare and treasured material in the "Game of Thrones" universe. Forged with dragon fire in a civilization lost to time, the super-sharp, super-light and super-strong blades are mysterious even to those who wield them. Turns out they're pretty mysterious to real-world chemists, too.

As Consell explains in the video (and in more detail on his blog), steel is an alloy: a mixture of metal and some other material. Steel is mostly iron, but it has a lot of carbon mixed in. Carbon makes the steel hard, but that also makes it more breakable. So to get a sword that was both incredibly hard and incredibly durable, you'd need to experiment a lot.

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But the most confusing thing about Valyrian steel is its appearance: Martin describes it as being beautifully swirled, and his characters frequently say that its mixed color comes from being folded thousands of times. This is probably a reference to real-world Damascus steel, which has a similar appearance (and which we've also lost the forging recipe for).

The problem is that this folding isn't actually a sign of good steel. From Consell's blog:

Folding metal and forging it out doesn’t do anything good for a blade. It’s actually bad for it. Every fold adds inclusions into the material; bits of oxide, soot, sand and other impurities from the environment would work their way in and mess up the steel. The actual purpose of historical pattern welding is to mitigate a problem. The problem being that they have good smiths but bad steel.

In fact, Damascus steel — which researchers think got its strength from strong wirey nanotubes that ran through the blade — probably wasn't actually that strong by modern standards. It was just impressive in the 18th century, which probably wasn't all that hard to achieve.

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Consell also points out that one of these swords was melted down and reforged into new blades, maintaining that well-known color pattern. That means it definitely wasn't folded. So either George R.R. Martin needs to read up on his smithing techniques (perish the thought) or his characters are just repeating incorrect sword lore they've heard on the street.

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Maybe Valyrian steel isn't steel at all: Modern super-materials called metal matrix composites (which are metal frameworks embedded with ceramics) could fit the bill, but they're really hard to make even with high-tech equipment — or magic.

Need more fantastic science? Reactions also has a video on a "Game of Thrones" poison called "the strangler":

And if you really want to spend all day trying to make a mythical realm scientifically plausible, you can dive right into the theories around the wonky seasons of George R.R. Martin's world. Because winter comes, but not for four months every year. Or on any regular schedule at all. Obviously.