All stone, when heated, emits far infrared light. The denser the stone, the more light it emits. Granite, being very dense, emits a lot of far-infrared light. Our stone is made by Dailyo in Japan. It’s literally state-of-the-art: We contacted Dailyo after learning that they had discovered a new source of granite in India that emits more far-infrared light than any stone ever tested.