Yep, in the latest patch if you give Gale the book in dialogue after putting the amethyst in outside of camp, he’ll initially say he’ll keep it for later and next time you’re in camp he’ll consume it (and in the meantime it doesn’t actually show in his inventory). I think you might also be able to give it to him like any other magic item if you put in the amethyst and don’t open the book, but haven’t tried that lately.
If you have Gale interact with the book after finding the gem and place the amethyst in it himself, then he’ll read it rather than consume it.
I assume this inconsistency will be addressed in the full release.
(And if anyone else opens the book, Gale won’t be able to consume or read it.)
