Black Tourmaline is electrical in nature and provides a connection between the earth and base chakra (which is the foundation of physical and spiritual energy in the body). This is why it is great to use for grounding. It also creates an equivalent of an electrical force field around your aura so lower vibrations will bounce straight off you. You can use this stone to purify and neutralize your own thoughts and internal conflict, it will even transform dense energy into a lighter vibration. You can also use this to help protect yourself against electromagnetic smog from mobile phones and computers etc.
Black Tourmaline promote detoxification, relieve stress and anxiety, increases alertness and protects you from stressful and negative environments. It really works on all areas physically, emotionally and mentally.
I use it to help ground and protect my sensitive kiddies from any lower harmful energies. They can put in in their pocket or carry it in their school bag. I even place it in their pillow slip if need be.
This stone is also great for protecting a space by placing a stone in each corner of the room creating a crystal grid of protection.
Be sure to regularly cleanse your crystals.