Fluorescence and Phosphorescence
A uranium glass marble and a rhomb of calcite respectively fluoresce and phosphoresce on a small shortwave (UVC) ultraviolet light. The uranium glass marble exhibits a yellow-green fluorescence. This type of calcite exhibits blue phosphorescence when stimulated with shortwave UV light: it will continue to glow for a few seconds after the UV source is removed.
The marble is about 1.5cm in diameter. Both are transparent under normal light; the calcite is colourless while the marble has a slight yellowish tint.
50mm F/4.0 ISO200 30s