Black Obsidian is known as the 'protector' crystal. This crystal will ground you during difficult circumstances and when things are happening beyond your control. It will guide you to the root of your troubles and protect you against negative thoughts, directing you to channel them and focus you to use transform this energy in positive ways.
Spiritual: stone of protection
Soul: protects you from shadow traits - addiction, fear, anxiety, and anger
Mental: acts as a mirror to your inner self - a stone of self reflection