Very Tenebrescent Sodalite (Hackmanite) with Winchite - Badakshan, Afghanistan
Sodalite from Afghanistan (Hackmanite) is very tenebrescent. Upon exposure to UV (shortwave or longwave) it changes its natural color to a deep blue. This change happens in seconds. After a few hours/days in bright white light it fades back to its original color (very different from Greenland hackmanite which can fade just as quickly as it deepens in color). The animation to the left shows this color change upon exposure to longwave and the shortwave UV.
The fluorescence under longwave UV is a bright orange. Under shortwave and midwave the color shifts to a whitish color. Very interesting (to me) is that it takes a noticeable amount of time for the fluorescence to setup under SW. Since these pieces are also very phosphorescent (see pic below) it seems that it takes a while for the electrons to get "excited" (the same characteristic that causes phosphorescence - takes a while for them to get "unexicted" - see this discussion on fluorescence for an explanation). Note the slight difference in brightness in the two shortwave pics - one showing the initial fluorescence, the other after a couple of minutes).
The winchite fluoresces a dull ye/grn with spots under shortwave. Click any pic to see larger images.