Black Tourmaline is something like a carbon filter for energies!
It's an amazing crystal for protection, detoxification, EMF reduction, and purification. Some call Black Tourmaline a grounding stone, although it's more of a stress-reducer which leads to grounding as a side effect of having a clearer energy field.
While being protective, Black Tourmaline does not put a damper on our vibration, allowing us to proceed in rising through our spiritual journey. It is known for being calming and soothing, as it pulls out all of the unnecessary energies from our fields. Black Tourmaline is also an excellent stone to use as a protector when we sleep as it shields us away from opportunistic energies that reside on the Astral plane.
Carry on receptive side for protection, and on dominant side (or on exact locations of your body) for purification. Stand your towers on your desks, nightstands, or between you and any electrical object to shield you from unwanted energies!