Tenebrescent sodalite, with chkalovite, tugtupite and uranyl, from Greenland
Very nice cabinet-sized specimen consisting of tenebrescent sodalite (orange fluorescence under all UV wavelengths, brighter LW), with small dots of chkalovite (blueish-white fluorescence under shortwave and midwave UV), minor tugtupite (red fluorescence under shortwave UV), and some green fluorescing uranyl salts, from Tunuliarfik, Ilímaussaq complex, Narsaq, Kujalleq, Greenland.
In the first picture, the specimen is shown fluorescing under a conventionnal 254 nanometers shortwave UV lamp (low pressure mercury vapor arc tube); then in the second image, the response under the new 255 nm high power UVC LEDs is shown. Under 255 nm UVC LED light, the sodalite barely reacts; this is due to the fact that, unlike standard 254 nm UVC bulbs, 255 nm UVC LEDs produce a very narrow spectral emmission, while mercury vapor bulbs have an output peaking at 254 nm but also emit some UVB and UVA radiation, which make the sodalite fluoresce brighter.
In the third image, the shortwave UV phosphorescence/"afterglow" is shown. Then in the next pictures, the midwave UV (310 nm UVB LED) response, the longwave UV fluorescence, the tenebrescence and the natural color of the specimen are shown.
Shortwave UV (254 nm)