In the thirteenth century version of English, that purple quartz we know as amethyst was either spelled amatist and ametist. Before that, in Old French (from whence it came), it was ametiste, and before that, it came from Greek amethustos, probably through Latin by one means or another. Oh, yeah, and amethustos translates to mean "not drunk". How could this be? Well, the Ancient Greeks had a peculiar belief that amethysts could prevent intoxication- there were several myths about the god Dionysus interacting with the stone, though some were of questionable origin. The point is, they had this superstition, and it was strong enough to name a rock after a state of sobriety, so there you go. The word amethustos affixes an a- to negate the rest of the word (even in English, it remains as a prefix meaning "not"), and thus methustos means "drunk". This is a formation from methus, which meant "wine" and not some other drug you're all thinking about. Surprisingly, methus is from medu, the Proto-Indo-European root for "honey", which makes wine a pretty sweet thing.
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd