A major component of rock collecting (for us) is simply getting out in nature. A buddy dragged us out to a very remote area here in middle Tennessee to hunt for fluorescent green agate. Since we consider ourselves pure "Glow Hounds" we weren't anticipating any glow rocks, just the beauty of the area, but we brought our UV lights anyway.

Small delicate crystals of bright green fluorescing quartz are peppered around a matrix of calcite on this striking specimen.

Red sodalite is named for the color it takes on when exposed to sunlight; it is nicely tenebrescent under longwave UV. Under shortwave UV the color deepens, in seconds, to almost black in some areas. 

Rarest of the rare from Greenland - apatite has only been observed in a handful of pieces over the decade+ we have been exploring Greenland. Blue apatite crystals fluorescing under UV.

Crack it! This has been our mantra for years, told to new folks we've guided into the mountains of Greenland. For ten years, we guided groups of 5 to 7 people into the mountains and put them on the best collecting spots in the Ilimaussaq Complex. 

This material is striking. The sodalite appears as crystal blebs in matrix, with a few spots of tugtupite encircling a bright white chkalovite.

Many minerals exhibit an afterglow or phosphorescence when the UV light is turned off. This glow can last for milliseconds or hours depending on the mineral. Some are very bright while others are barely perceptible.

Tenebrescence of Greenland fluorescent sodalite is amazing. This is a piece of a deeply tenebrescent sodalite. Note how when the shortwave light is first turned on, the sodalite fluoresces a bright orange but almost immediately shifts to a burnt orange as the tenebrescence sets in.

The Garpenberg mine is located in Bergslagen, a very old mining area in the southern part of Sweden.

The mine is very active today and is one of Europe's most progressive underground mining operations. Collecting is not possible, and the few specimens that reach collector's hands are highly prized. The mineralogy is quite similar to that of Franklin NJ. 

Fluorescent minerals can be fascinating to those who discover these hidden treasures and they often raise various questions. Here are some common questions related to fluorescent minerals.

Fluorite often times has bright fluorescence under ultraviolet light, revealing bright colors that range from purples and blues to brilliant greens and pinks. Anyone with a fluorescent mineral collection probably has a piece of fluorescent blue fluorite, the most common fluorescent color for this mineral.

The sun was slowly setting so we made dinner and relaxed a while (amazing how slowly the sun sets when you're waiting for it). Once it got dark collected started in earnest. The first thing you notice is the bright blue hydrozincite everywhere on red calcite. All of the small rocks glow. We proceeded to check out the large boulders laying around on the surface and quickly determined that dozens of prior collectors had done the same. That's why they're still lying around.