This stone forms during regular volcanic eruptions, where ash (scoria) is expelled from the mountain and flows down the slopes. The rapid cooling of this hot material results in a structure with significant open spaces. It has an andesitic composition with abundant ferromagnesium crystals and traces of sulfur. Despite its high porosity and permeability, the stone is remarkably resistant to fungi. When wet, it absorbs water, transforming into a beautiful black color. The stone is extremely durable and suitable for tiles, known for its hardness and strength. In full sun, it can become warm, but the air within the stone moderates extreme temperatures. Ideal applications include water features, swimming pools, and cladding.