Their beautiful color is created by an environmentally friendly ceramic stain that absorbs into their porous material. Ideal for indoor and outdoor usage, lite stone fire rocks all-weather ceramic base construction ensures the elements cannot harm them. In addition, these ageless lite stone balls will survive extreme weather, sizzling hot or freezing cold, and are temperature tested and fire approved. They will not smoke, create ash, or harmful fumes and they burn cleanly. Uniform in shape and size, these stones make a wonderful accent in your backyard fires.