Apparently d12’s were the key to the future for a French author named Jean de Meun (c. 1240-c. 1320) who wrote a book called “Le Dodechedron De Fortune,” the cover and dice pouch for which can be seen over here. It was apparently a “for funsies” method of divination that was popular enough to see reprinting over 200 years after he died. There’s an English translation called “The Dodechedron of Fortune,” (that spelling of dodecahedron is “ye olde spellinge,” so you might search all versions if you’re inclined) but the most I could find for that edition is on this page, which just has links to the title page and a few pages of fortunes.

I did come across the entire book, but in the original French version from 1574. C’est la vie, non?

So there you have it. The d12 isn’t just for great axe damage and a few spell effects in your tabletop game, it also tells fortunes! I suspect it’s probably still jealous of the d20’s that are in Magic 8-Balls, but it gets bragging rights about being the original thing, right? :)