So, I have the dang creepy book, I have the amethyst. Whenever I try to read it there's no option to give it to anyone, just read, destroy, or put back. I'm in Act 2 and I haven't
gotten to the towers yet, exploring a bit more first after doing the inn quests and healing the tranced fist.
For Astarion:
I've had the conversation where you copy his scars onto the ground for him to look at and we seem chummy enough.
For Gale:
He's had the "Oh hey, you need to suicide bomb yourself" conversation and is no longer asking for enchanted items to munch on. I had the weave scene with him early on and he's also stopped me after combat and basically said he wants to go to bone town with me.
I got the book and amethyst before any of this though and slotted the stone into it. Did I miss something?