Blue Obsidian Gemstone Obsidian is truth-enhancing. A strongly protective stone, it forms a shield against negativity. It blocks psychic attack and absorbs negative energies from the environment. Obsidian draws out mental stress and tension. It aids in astral travel , facilitates divination and enhances telepathy , supports communication skills in healing. Blue Obsidian opens the aura to receive healing energy . Price is for one stone. Stones vary in shape and size. Sizes are approx.