Mica

Mica is an excellent protection mineral, as it is not only insulating, but its reflective surface also deflects negative energy and psychic attack. Because of its non-conductivity, it is also very helpful in creating a shield from electromagnetic radiation, and can be placed on a desk between the user and a computer.
Mica is also used to reduce hostile or nervous energy.
I like to use it as a reflection to see the true self.