Placing crystals in your environment is helpful in the absorption or transmutation of energies. Here are some suggestions to get you started.
A piece of smoky quartz or black obsidian will absorb negative energy.
Amber and bloodstone cleanse and transmute energies.
Black tourmaline, jet, fluorite and black jade return energies that have been directed towards you back to their source – as does a mirror placed facing the direction from which psychic attack emanates.
Rose quartz and amethyst attract protective, loving energies.
Turquoise clears environmental pollutants and malachite is helpful if you live near a nuclear power station.
Source: Thorsons Way of Psychic Protection by Judy Hall.