Material: Color: as the picture shows Glow Rocks For Landscaping Can Continue To Glow For Several Hours When It Absorbs Enough Energy, And Will Slowly Dim As Time Goes By Until It Stops Glowing. Reusable To Brighten Your Yard For Decades. In Fact, It Also Glows During The Day And Consumes Energy Continuously. This Is One Of The Reasons Why It Replenishes Energy During The Day But Does Not Glow At Night. Glow In The Dark Gravel Can Absorb And Store The Energy Of Light Source (sunlight, Strong Light, Or Other Light Sources) And Bright . The Darker The Surrounding And The More Exposure To Visible Light, The More Bright Glow Can Be Seen. The Smaller Sizes Are Suitable For Use As Fillers. For Filling Garden Paths, Vases, Potted Plants, Fish Tank Gaps, Or Creating Glow-in-the-dark Sand Art Bottles And Micro Decoration. Mini Glow Sand Is Suitable For Yards, Gardens, Pathways, Fish Tanks, Vases, Potted And Creating Glow In The Dark Sand Art Bottles And Micro Decoration. Open The Packaging Bag Before Using In The Dark Sand, Spread Sand Evenly And Expose It To Sunlight, Strong Light Or So That Each Glow Sand Can Fully Absorb Energy. It Will A Fantastic Light In A Dark Environment.