This is a kind of simulation photoluminescent pebble, made from photoluminescent materials produced by the Company, radioactive and toxic free. After ten minutes of absorption of natural light, it can give off identifiable natural fluorescence in the dark or at night for the next 8 to 10 hours. This product is applicable to scenic spots, City Park, home balconies, courtyards, fountains, fish tanks, and any other decorative applications to beautify the environment.