CrazyDeal Glow in the Dark Pebbles Stones adorable nice 100pcs Home Garden Walkway Fish Tank Decoration Line a walkway, edge a flower bed or fill a planter with these unique pebble stones. After being exposed to daylight, these pebbles glow (sky blue) in the dark. Glow lasts approximately two to three hours after full sun exposure. Material: Photoluminescent pigment + resin. Color: Colorful,blue,yellow green.