 | All minerals have the ability to reflect light. That is what makes them visible to the human eye. A few minerals have "fluorescence". These minerals have the ability to temporarily absorb a small amount of light and an instant later release a small amount of light of a different wavelength. This change in wavelength causes a temporary color change of the mineral in the eye of a human observer. |  |
 | The color change of fluorescent minerals is most spectacular when they are illuminated in darkness by ultraviolet light and they release visible light. Fluorescence has many practical applications, including mineralogy, gemology, chemical sensors (fluorescence spectroscopy), fluorescent labeling, dyes, biological detectors, and fluorescent lamps. |  |
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