ἀδάμας

Ancient Greek ἀδάμας (adámas) combined the negative prefix a- with damáō (to tame, to conquer), producing a word meaning untameable, unconquerable. The Greeks applied it to the hardest material they could imagine—sometimes iron, sometimes a mythical substance harder than anything in nature. Hesiod placed adamant in the sickle that Kronos used to castrate his father Uranos. The word was born in myth.

Latin borrowed the word as adamas, adamantem, and applied it increasingly to actual hard stones. By the medieval period, the word had split into two lines: adamant, meaning inflexibly hard or unyielding, and diamond, which evolved through Latin diamas, Old French diamant, and arrived in English with the same Greek root barely recognizable beneath the phonetic changes.

English adopted adamant by the early fourteenth century, using it both as a noun (an impossibly hard stone) and an adjective (stubbornly immovable). John Milton gave Satan a throne of adamant in Paradise Lost. The word carried a moral charge: to be adamant was to resist all persuasion, for good or ill.

Modern English uses adamant almost exclusively as an adjective meaning firmly resolved, refusing to change one's mind. The mythical substance has evaporated; only the metaphor remains. But the word still carries its Greek defiance. To be adamant is to declare yourself unconquerable—to become, for a moment, harder than any stone.