Thermoluminescent Sodalite (Hackmanite) from Afghanistan
I was preparing for a photoshoot tonight, cleaning the specimens of all the lint and hairs that tend to accumulate on them. I was using a MAP torch to lightly burn the little buggers from all the nooks and crannies (a hint learned from the Fluorescent Mineral Group on FB). Much to my surprise, a piece of Afghan sodalite started fluorescing! Decided to do some experimenting.
Found another piece (one without any valuable crystals) to play with - same thing. Heat it up with the torch and it glows like a banshee. So - let's see how heat sensitive this material really is. I set a pot of water on the stove and heated it to boiling. Dropped the sodalite into the pot and bazinga - instant phosphorescence. Took it out and ran it under some cold water, goes away instantly. Put it back in, instant response. Did this several times - amazing.
Next, I brought it outside and checked it out with the torch. Same response as the other piece - the sodalite fluoresces just as if it was being hit with a strong LW UV light. Apparently boiling water is not enough to cause the strong org/yel fluorescence, but works great for bringing out the same color as when the piece is phosphorescent (and keeps glowing until the rock is cooled off). But apply a certain amount of heat and it's just like using a UV light. (Sorry - I just don't have the instruments to conduct the experiment more precisely).
So I moved the rock and the torch to my photo studio (unwilling to stick a pot of boiling water inside it though). Set the rock on a ceramic tile and took the normal pics - SW, LW, natural, and phosphorescent; these are shown in the gallery below. Then heated up the base of the rock with the torch, extinguished it, and snapped a pic. The result is shown in the big pic below. The fluorescence is best where the torch was directly applied, but note the phosphorescent color towards the rear of the rock. Apparently the rock got hot enough that it seemed to phosphoresce in areas far enough away from the torch. (I think the torch makes the rock too hot for phosphorescence; was not able to note that when heating with the torch outside.)
I was not able to test (immediately) whether the heat affected the tenebrescence of the sodalite. Afghan sodalite is almost impossible to fade quickly. I will check it in a few days.