Valyrian steel, in the Game of Thrones universe, is a seemingly magical metal — an alloy that's stronger, lighter, and sharper than common steel. Dragon fire seems to be involved in making it, but the exact recipe (in the timeline of the show and the "A Song of Ice and Fire" book series it's based on) was lost centuries ago.
In this American Chemistry Society video and an accompanying blog post, material scientist Ryan Consell considers a very important question: how, exactly, would one make Valyrian steel in the real world?
His conclusion: Valyrian steel, in all likelihood, isn't steel at all.
Steel is an alloy, mostly made up of iron and carbon atoms. Different proportions of the two — as well as the addition of other elements — can alter the metal's overall characteristics.
Valyrian steel's hardness and durability seem most similar to an alloy called spring steel (which incorporates silicon and manganese), but spring steel doesn't have Valyrian's extreme resistance to heat. Meanwhile, there's a class of air-hardened steels (which incorporate a precise blend of chromium, nickel, silicon, molybdenum, manganese, and vanadium) that are resistant to heat, but they're not quite as hard. And no steel, most important, is appreciably lighter than the others.
All this leads Consell to conclude that the most likely match for Valyrian steel is a class of materials called metal matrix composites: complex materials that incorporate both metal and harder materials, like ceramic, to provide a combination of strength, sharpness, durability, and lightness. A titanium silicon-carbide composite, he suggests, seems reasonable, though it's currently an experimental material that requires vacuum chambers to make and currently costs more than $1,000 a pound.
Hat tip to Rachel Feltman at the Washington Post for the find.