Line a walkway edge a flower bed or decor garden fish tank with these unique pebbles. Glow lasts approximately two to three hours after full sun exposure Quantity: 100pcs/lot Size: 2-3cm/0.78-1.18inch Colour: mix/white/green/yellow/rose red/blue Material: Photoluminescent pigment + resin Q: Will the luminous stone not shine is it invalid? A: The luminous stone is a light-storing product. The principle is that it can emit light by absorbing the light source. Each time the light is emitted is 8-12 hours during which the first 1-2 hours is the high light period and continues to glow. The received product did not emit light because there was no absorption light source during the logistics. As long as you get sunlight or light for a while you can shine again Q: Why do I have a day's sun during the day and it is still not lit at night? A: Because the principle of luminous is to absorb light and emit light which means that it begins to glow in the process of storing light. If the light is absorbed during the day but after a dusk time the luminous period of the luminous light is over, so you can only see it slightlyWeak light, but when you turn on the lights you can see very bright Q: What is the brightest color of luminous stone? A: The luminous stones are luminous in white color such as bright yellow green blue green and green. Other colors are colored with yellow-green powder plus color powder. The toner will cover the glow of luminous powder. After being exposed to strong daylight with 3 hours these pebbles can be lighted within 1-2 hours in the dark Note: Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you