Everything is vibration.  Crystals and gemstones have a stable vibration that may be utilized to affect a change in an energy system.  Different stones have a different vibration that may affect us physically, emotionally, mentally and spiritually. In a session, this is done by a laying on of stones on or around the body.  Typically, they may be laid on major energy centers of the body (chakras).  The use of crystals and gemstones during an energy healing session amplifies the energy that can be utilized by the client and they help create a space of relaxation and awareness.