This is one of the more tenebrescent varieties of sodalite from the Ilimaussaq Complex, Greenland. We discovered it one year in the same area where blue sodalite is found, but these pieces were extracted from a vein within a cliff just prior to the blue sodalite deposit. Perhaps they are blue sodalite "being born?" - their natural color is more of an off-white. But tenebrescence reigns supreme (see the animation at the bottom).
Sodalite (Hackmanite) under shortwave UV, green fluorescence unknown
Tenebrescent
Natural
Longwave
Animation showing tenebrescence
Size