These are basalt stones in front of me. As you can see, there's two different colors here. We have the black and this. And this is actually the same stone. The stones start out being this color and after they have the oil applied to them with the massage, they remain black for the rest of the life of the stone. Basalt stones originate in the mountains and are actually river rocks. They commonly are shaped in these wonderful oval shapes that are typically palm sized. This is the most common size that there is. Basalt stones are also great heat and cold conductors. Which means that if they have heat applied to them for any amount of time, they will retain that heat continuously for hours. And, the adverse is true. If they're cooled, they will remain cold for many, many hours. This obviously is very beneficial in many types of treatments, and hot stone massage is the most popular treatment. And that is what a basalt stone is.