This material is very tenebrescent and also very phosphorescent. It takes a while to fade (put under very bright light). Also present is winchite (varying fluorescence) and probably some richterite, as well as yellow fluorescing phlogopite (SW). An animation shows the color change and a composite compares the various states this rock presents. Click any thumb below for bigger pics. SW, MW, LW, Phos, and tenebrescent pics in that order.