This stone is formed during regular volcanic eruptions where ash (scoria) is blown out of the mountain and flows down the slope. This hot material cools down quite fast with much open space in its structure. The andesitic composition with lots of open pore space, makes the stone hard, with high permeability and porosity, and further it’s rich in ferro- magnesium crystals containing some sulfur. This combination makes the stone very porous, but resistant against fungi, when wet the absorption of water turns it into a beautiful black colour. Stone is also suitable for tiles, being very hard and strong. In full sun it becomes hot, though the air in the stone prevents extreme high temperatures. Recommended use for water feature and cladding.