More From the Desert Floor

As a beginning florescent mineral collector I am excited about what I am finding, even if my discoveries are routine for the seasoned vet.

In a recent post I described how happy I was to find a rock with afterglow in an area not written about by collectors. Just last night, though, I discovered something else: one of my rocks fluoresces a different color in different wavelengths.

Normally, a rock or mineral will respond either well or poorly to a certain wavelength. Most materials reacting to shortwave will sit quietly under longwave.  And longwave materials respond weakly to shortwave.

What’s different with this chunky piece of field opal, or something like that, is that it changes colors under different wavelengths. The first photo is visible light, the second shortwave, the third longwave. Some calcite will change into a different color under all wavelengths, that including midwave.

I discovered this change accidentally last night as I was looking over my small group of rocks from my Sunday field trip. In the future I will be sure to check if any rock changes color, not just if it lights up. Multiple wavelength response is something collectors look for and something I will look for, too.

Visible light

Short wave

Long wave


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