Japan. According to Japan's Fuji TV website, Japan's Okinawa Prefecture and other places on the coast of a large number of pumice, a large number of pumice has filled the nearby coast, the people's lives have a small impact. Pumice refers to a volcanic eruption after the cooling of magma formed a mineral, the main component is silica, soft texture, small specific gravity can float on the water surface, so it is called pumice, also known as river foam stone.