Crystals can be an amazing aid in protecting yourself, your home and your energy...
Wearing crystals can help to protect you from negative energy and lower frequencies, while turning the negative energy into positive.
One of the most powerful and beneficial stones for this is Black Tourmaline. Black Tourmaline can help turn negative energy into positive, while keeping you grounded and optimistic. Black Tourmaline can also be placed around your home or in your car, but wearing your crystals will keep you protected where ever you are!
In general, many of the dark or black crystals will be very useful for protection and grounding.
Black Obsidian, Shungite, Hematite and Pyrite can all help protect you from negative energies and EMF - while helping to keep you grounded and focused,