Obsidian

Great stone of protection, able to block psychic attack. Grounding this naturally occurring volcanic glass formed as an extrusive igneous rock. Obsidian is produced when felsic lava extruded from a volcano cools rapidly
The spiritual meaning of Obsidian is that it is the ultimate stone to confront your shadow self. If you set the intention to face your shadows and prepare yourself for overcoming your most traumatic fears, it can be the stone that brings you the most transformational experience to your life.