Fluorescent /UV-Reactive Minerals

  A feature of some minerals is fluorescence -- the ability to absorb invisible UV (UltraViolet)  light, and to emit the absorbed energy as visible light. While it may sound trivial, it is delightful to observe in reality. In general, the molecules of trace elements\are the source of the fluorescence, such as chromium which causes rubies to fluoresce a deep red, or uranium in hyalite opal which fluoresces a bright green. Some minerals are not consistently fluorescent – kyanite, which often occurs with ruby, typically does not fluoresce, but some specimens fluoresce with the same red as rubies do, indicating the presence of chromium.

Some fluorescent minerals also exhibit phosphorescence, which is the ability to continue to emit visible light after the UV light source is removed. Phosphorescent minerals are much rarer than fluorescent minerals.