Adamantine is a legendary substance dating back to the middle ages, and perhaps beyond. It was basically meant to be the hardest substance on earth—though whether it is metal or gemstone varies. Adamantine has captured the imagination for centuries because of the qualities it is meant to have—it is supposed to be unbreakable, untarnishable, lightweight (good for armor), and of enormous strength. Basically, someone with armor and sword made from adamantine would be nigh unbeatable.
Of course then the question is how something can even be forged out of such a material, but usually this slight complication is done away with by being a gift of some type of supernatural power, whether that be faerie or deity or what-have-you. The gates of Tartarus are supposed to be guarded with a gate of adamantine, for example, and it was this material the gods used to chain Prometheus. Adamantine is even mentioned in John Milton’s Paradise Lost, where Satan’s shield is described to be of “ten-fold adamant,” and the angels’ armor is of adamantine, while also making appearances in The Faerie Queen, and one of John Donne’s poems.
Probably the most recognizable modern adaptation of this remarkable metal is the Adamantium of the Marvel Comics universe—an alloy that must be kept boiling because once it cools it is virtually indestructible. It is this metal that is grafted to Wolverine’s bones, along with appearing in a dozen other ways. In this case, it is science, and not mythology, which has created so strong a substance, but the outcome is the same.
What I like about adamantine is that it’s basically a Utopian trope—perfect, and therefore impossible. But the idea, the possibility of adamantine has existed for centuries… all because of fiction, basically, and that’s a pretty awesome thing. Good on you, fiction. Good on you.