Hot stone massage is a specialty massage where the therapist uses smooth, heated stones, either as an extension of their own hands, or by placing them on the body while they massage other parts of the body. The heat can be both deeply relaxing and help warm up tight muscles so the therapist can work more deeply, more quickly.
Basalt is a strong, smooth volcanic rock that contains iron and magnesium, which allows it to absorb heat. It's normaly found on the ocean floors and lava flows. The stones come in various sizes and weights, from large to small, with small stones used on the face and feet and larger rocks used as tools to work muscles in different areas of the body.