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Black Light. What is it? It is a portion of the Ultra-Violet Spectrum that is invisible to our eyes. We can not distinguish it. However, when this radiation impinges on certain materials visible light is emitted and this is known as "fluorescence." Fluoresce ....

Middle of Essay
.... It is then in an unstable environment causing it to fall back into its original orbit. This process releases energy, and if it is in the visible part of the spectrum, we have a transient light phenomenon. Ultra-violet light is an exciting agent which causes luminescence to occur. There are many materials which exhibit fluorescent characteristics. Many of which are even organic. Teeth, eyes, some portions of the skin, and even blood exhibit fluorescent qualities. Naturally occurring minerals such as: agate, calcite, chalcedony, curtisite, fluorite, gypsum, hackmanite, halite, opal scheelite, and willemite, also have similar characteristics. ....