I recently received a box full of fluorescent minerals to examine. Fluorescent minerals contain crystals that glow (fluoresce) when exposed to ultraviolet light.  As you can see, the effect was beautiful.

Minerals under regular light
Minerals under our Ultraviolet (blacklight)

Try This:
A blacklight is a great item to have in  your science collection. Here is a great nightime science activity that you can try with your kids. Get an inexpensive battery powered blacklight, They are available on our web site or at many party stores or hardware stores. Go into a dark room and switch the UV light on. Now start looking around. Open drawers like toy drawers, clothes drawers, and closets. Many surprising objects are likely to start glowing. White clothing, “neon” colored paper, glow-in-the-dark-objects, even tonic water will glow under a blacklight.Try writing notes using a highlighter marker under the blacklight.

How does it work?
The light waves from an ultraviolet light (blacklight) excite the molecules of certain materials enabling them to reflect back light. In the case of fluorescent minerals, the light that is reflected back is often an entirely different color than the original mineral. Minerals such as calcite, wernerite, and willemite emit a bright colorful glow. Depending on where you live, you might be able to go out at night and find some fluorescent minerals of your own. Did you know scorpions glow under ultraviolet light? Get out and see what you can explore with a blacklight!