... dark. Chargable by sunlight or lamp light, even UV light source for minutes.Material: Sulfide Zinc based.Appearance: Orange crystal powder ... .Average particle size range: 20~25um.Luminous color: Red.Free of dangerous, toxic, heavy metals, radiation. Friendly to ... (glow in yellow-green, blue-green, sky-blue, blue-purple, red, orange, etc.)2. Glow in the dark plastic products: printing ...