Hot stone therapy is a variation on classic massage therapy. Massage oil is first applied to the body, which allows the stones to glide smoothly along the muscles. The stones used are normally lava or basalt, a type of rock rich in iron that retains heat. These stones are heated to a suitable temperature and used to massage the back. After the massage with the stones is completed, the treatment continues with a normal massage using Swedish techniques. When this is completed, the hot stones may then be placed on key points on the body and left for a short period of time. Depending on the length on the massage, this can then be repeated on the front section of the body. The massage is effective for back pain, poor circulation, stress relief and tension.