Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation. However, when the absorbed electromagnetic radiation is intense, it is possible for one electron to absorb two photons; this two-photon absorption can lead to emission of radiation having a shorter wavelength than the absorbed radiation. The emitted radiation may also be of the same wavelength as the absorbed radiation, termed "resonance fluorescence". (by Wikipedia)
Cobaltocalcite (Click in: http://www.mindat.org/min-1094.html)
Berilo (view in: http://www.mindat.org/min-819.html)
Prehnite (view in: http://www.mindat.org/min-3277.html)
