This is a word that comes up often in RPGs...
Adamantine -- Rigidly firm; unyielding.
The Greek and Latin word for the hardest imaginable substance, whether applied to a legendary stone or an actual substance, such as diamond, was adamas. Latin poets used the term figuratively for things lasting, firm, or unbending, and the adjective adamantinus was applied in similar contexts. The English noun adamant (meaning "an unbreakable or extremely hard substance") as well as the adjective adamant ("inflexible" or "unyielding") came from adamas. Adamantine, however—which has such figurative uses as "rigid," "firm," and "unyielding"—came from adamantinus. Adamas is also the source of diamond. Diamas, the Latin term for diamond, is an alteration of adamas.
And my apologies in advance for my attempt at humor... those of you who lived through the 80's will get it!
