Experiment #42 Off-Color is a variation of UV reactive golden yellow rods. This campaign was produced during the process of making NS-146 Nova UV reactive yellow. As a flame and color stable glass, Exp. #42 Off-Color is nearly clear under natural light but fluoresces a golden yellow under an ultraviolet light. For best results, use a UV 365nm-395nm LED flashlight . These rods vary slightly in air content & UV reactivity. Uranium was used to produce this glass.