Fluorescent Rocks

The Museum's fluorescent rock display consists of two cases side by side containing dozens of rock and mineral specimens and a few fossils. The four links below show what colors are possible. Each shows the same image under the three lighting situations (normal cool white, longwave UV and shortwave UV) with the ability to rapidly jump between them.

For best results wait until all images are loaded after choosing a link.*
All colors Eerie blue    
Yellow-orange Green/orange

Some minerals are fluorescent under ultraviolet light (UV). The reasons for fluorescence are technical and need not be discussed here. The important thing is that the colors displayed under UV are like nowhere in nature. And different colors are displayed under longwave UV and shortwave UV (although most minerals that do fluoresce tend to only under one or the other).

Longwave UV (at 365 nanometers) lies in the UV-A part of the light spectrum. You can buy blacklight lightbulbs in stores, in case you want to try this out at home.

Shortwave UV, on the other hand, lies in the UV-B part of the spectrum and encompasses rays that can cause sunburn, so you're not going to find shortwave lightbulbs in the stores.

Though some minerals are known to fluoresce, samples from the same specimen may fail to consistently. Only some fluorite (from which the term 'fluoresence' is derived) will glow an eerie blue. (It's thought that the inclusion of organic materials or rare earth ions in the crystal structure is the cause of its fluorescence. ) Willemite from Franklin, New Jersey, almost always fluoresces (because it contains manganese), but willemite from other localities will not. Here's a list of minerals known to fluoresce and the colors they show:


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* These pages were designed on my tiny 13" monitor. The effect on larger screens may not be quite as stunning. In fact, they may look downright dopey. I haven't had the opportunity to test these pages are larger monitors yet.