Tumbled Black Obsidian: Formed from rapidly cooled volcanic eruptions, obsidian is also sometimes called volcanic glass.  Metaphysical uses;  used for grounding, fostering psychic awareness and for clearing "psychic smog" (dense, chaotic or leftover energies resonating within our personal or physical space); often used for feng shui and is thought to have a strong ability to absorb negative energies, particularly psychic energies; a good crystal for use in conjunction with others during change to help maintain stability and grounding. Price is per crystal.