This black natural glass has been formed from the rapid cooling of lava. Because it is easily splintered into sharp fragments, obsidian has long been used in making knives, arrowheads and sculptures.
In healing circles, it is known as a stone of protection with grounding properties, it is often used to clear subconscious blocks and to absorb and disperse negativity. Beautiful and useful too! Pendulums are used much the same way as applied kinesiology or muscle testing to help determine the answer to a question.