Uhome 30 PCS Glow In The Dark Stones Fluorescent luminous luminescent Pebbles Rock photoluminescent stone For Fish Tank Aquarium Walkway - Perfect For The Garden(Sky Blue) Color: sky blue in the dark; Milk white in the daylight Material: Photoluminescent pigment + resin Note: Please expose the item to the sun in the daytime to absorb enough light, so that they can glow in the night better. Line a walkway, edge a flower bed or fill a planter with these unique acrylic pebbles Pebbles are about the size of cooked lima beans