A hot stone massage is a type of massage that uses smooth, heated stones to relax muscles, improve circulation, and relieve pain. A therapist places heated stones on specific points of the body and may also use them to perform massage strokes, often using the heat to penetrate deeper into the muscles than with just hands alone. The stones are typically made of basalt, a volcanic rock that retains heat well, and they are heated in a special warmer to a comfortable, safe temperature.