our Photoluminescent gravel stone is made from aluminate-stronium  photoluminescent pigment and synthetics material,with great weather resitant, and hardness

,this gravel stones can be shining glowing in the dark more than 10hours at night , after absorb the visible light for 5-30mins,and this emit and absorb light process is repeatedly.

Non-toxin,Harmless,non-radiation, Eco-friendly material

Glow color: green, blue, aqua

Size: ,3-5mm,5-8mm,8-12mm,10-15mm,15-20mm etc.