The phenomenon of fluorescence was discovered in 1852 by an English scientist called Sir George Stokes. He was fascinated by his observation that a specimen of the mineral fluorite appeared green in the shade, but glowed a distinct blue in the sun. Stokes named the characteristic fluorescence after the mineral fluorite. There are approximately 500 different kinds of fluorescent minerals. Most minerals that do fluoresce tend to be overpowered by the visible light spectrum, so it is best to view them in the dark.

Ultraviolet light is split into two categories: long wave and short wave.
Long wave is closer to the visible light spectrum and actually emits a bit of visible light in the form of a very dark, purplish glow. Long wave ultraviolet light is commonly referred to as a black light. Approximately 10% of fluorescent minerals react to long wave ultraviolet light.

Short wave ultraviolet light is invisible to humans and also harmful. This is the part of the light spectrum that causes sunburn and blindness. Interestingly, short wave ultraviolet light cannot travel through many materials, including glass and plastic, making it relatively easy to protect against. Approximately 90% of fluorescent minerals react to short wave ultraviolet light.

Although fluorescence is named after the mineral fluorite, not all specimens of fluorite actually fluoresce. Minor impurities, called activators must be present in the mineral structure. Therefore a pure mineral, i.e. the absence of activators, will not fluoresce. Specimens from the same mine or locale tend to exhibit similar fluorescence. Common activators include lead, manganese, molybdenum and the uranyl ion.