It’s a volcanic tuff stone deposited in seawater, below the wave beach area. The deposit has sedimentary structures, often emphasized by the fine grey/green clays dispersed throughout the stone. Chloritic cement is common and gives the grey/greenish color, which is strongly visible underwater. The stone must be installed with good circulation and filtering of the water (especially salt water) to prevent brown algae from forming. The presence of chlorite in the stone confirms its resistance to chlorine. This stone is very porous, so it needs proper installation in swimming pools using cement-glues designed for swimming pools. If used in bathrooms, we recommend using a good quality sealer to maintain the gloss of the stone tiles. It’s a unique stone with a very special color and wave pattern.