Aquamarine is good to protect against negative thoughts or any sort of psychic influence.
I also have a bone to pick with your explanation of amethyst... it heightens my awareness, and thusly, draws people's thoughts and emotions toward me, not the other way around.
Also, onyx is a good blocker in general. Though, sometimes it can block too much, it's a bit of a heavy hitter.
Tanzanite is good to absorb and store positive energy.
Obsidian is good at blocking (another heavy hitter), and storing negative energy. So well in fact, that you might have issues using it afterwards.