In this therapy smooth black volcanic rocks basalt are heated to a comfortably warm temperature in a heater and are then used to massage the body the heated stones are designed to work at the deepest muscle level and the heat serves to warm up tight muscles so as to allow the therapist to work on the deeper muscles quicker the heat penetrates deep into the muscles and tissues permitting the muscles to relax much faster in comparison to a normal manual massage it eases the tension built up