Last winter I spent a bit of time in and around Austin, Texas and I brought back some lovely black tourmaline that I've been waiting to work with. Here you can see a bit of the transformation:
Black tourmaline (schorl) is a powerful stone for protection against negative energies and for spiritual grounding. If this sorta thing floats your boat, you can read a bit more about some of Black tourmaline's properties here and here, or pick up a book about crystals & stones at the library, cause books and libraries are where it's at.