Jinan Realglow photoluminescent sand is produced mainly from the rare earth elements through a special technology, the sand can glow in the dark for up 20 hours after its 10-minute exposure to a visible light source. The glow in the dark sand is re-chargeable many times over just by exposing it to any light source, preferably those with Ultra Violet rays like Sunlight or UV. They are different from phosphorescent sand, photoluminscent sand is long decay time material which is based on rare earth.