Black Tourmaline is a must for any crystal owner. It transmutes negative energy and is highly protective. EMF blocking, and grounding, it's stabilizing energy is potent and calming. When Black Tourmaline is paired with reflective mica, it sends any ill will back to sender. Place a chunk of tourmaline near your doorway, to protect and guard the energies of your space, or place it at your root chakra, or between your feet while meditiating for grounding, stable energy. 
 
There are commonly natural fracture lines in black tourmaline. Black Tourmaline is a very brittle mineral, and may flake off during handling. Be sure to handle with care! Fracture lines may cause breaks into two  or more pieces, but just know it was meant to do so someday! In which case, you score multiple pieces!