Pendulums have been used for divination and healing for centuries, and are one of the simplest and safest forms known. A pendulum it a tool that allows you to connect with your higher self (the subconscious that is more aware of subtle energies than your conscious mind), and ask it questions or seek it's guidance.
Anyone can use a pendulum: Simply hold one end of the chain between your thumb and first finger so that the stone can swing freely in the air. Try to keep your arm still but relaxed; your higher self will control the fine muscle movements in your arm and fingers to move the pendulum and allow it to "speak" to you. Now ask the pendulum to show you "YES" -- it should begin to swing. Next, ask it to show you "NO" -- it should swing in a different direction. That's it, it's just that simple!