Brightly fluorescent both SW and LW. Most areas of green fluorescence is the typical uranyl activated mineral found on Ilimaussaq rocks. The material from this locality is probably the winner in the color-change department. Brightly fluorescent both SW and LW - the natural color deepens to a light pink upon exposure to LW UV (or obscure sunlight) and to a deep purple (almost black) after exposure to SW.
Upon exposure to SW UV the sodalite on this piece changes color to a deep purple - in seconds! Expose it to a bright white light (UV free halogen or LED spotlight held directly on the rock) and it reverts back to its natural color almost immediately.
The animation below shows the color change (tenebrescence) after exposure to longwave and shortwave UV.
They were nicknamed "Yooperlites" which is derived from the name “yooper”. A yooper is a nickname for the Upper Peninsula natives and these fluorescent stones quickly gained fame. After data was published on these fluorescent stones, it was discovered that sodalite is the actual true mineral that is fluorescing orange.
365nm UV light is often called "blacklight". Before the advent of longwave UV LEDs, blacklight fluorescent tubes, (the kinds used in hippie days to light up psychedelic posters) were the standard longwave UV light for our hobby. They were not very powerful but they did light a large area.
Enter 365nm UV LEDs
First, an animation showing the difference between the UV flashlight we recommend (365nm filtered UV flashlight) versus unfiltered 395nm UV flashlights we see many folks carrying around at shows. So. much. visible purple light. We selected a bunch of rocks as a demonstration. Took pictures of them under his flashlight without the filter and then with the filter.
