Minerals seen in fluorescent light. Mr. Rice writes, "This photo was taken during field work in a cave in Nevada, USA. One of the best things about being an amateur scientist is getting invited to participate in field work with professional scientists. My brother and I participated in a week of speleological surveys in and around Great Basin National Park, Nevada. In this photo, geologists are examining fluorescent calcite and other minerals using an ultraviolet "black-light." This particular light is optimized for mineral identification by selectively emitting two different wavelengths of light (UV-A, 365 nm, and UV-C, 245 nm), while filtering out all of the visible light. Everything in this photo is either fluorescing or illuminated from the emitted light of the fluorescent minerals. Recent studies suggest that this cave passage has remained little changed for the past 12 million years."
