Cubic yellow fluorite crystals on limestone matrix, collected in 2016 from a roadcut in Bedford, Indiana. This fluorite shows a very interesting fluorescent/phosphorescent response. Under short wave UV, the cubes fluoresce a bright off-white color, with white phosphorescence. The fluorescent response under long wave UV is a similar bright white, but with green phosphorescence. The largest crystal in these photographs (right of center) measures approximately 6.5 x 5.0 mm.
The fluorite occurrence from which this specimen was collected was confined to a relatively limited area of about 40 yards in length, between knee and head height. Other fluorite specimens were found at this location that showed similar fluorescence, but a markedly different phosphorescent response- blue after short wave UV, but with no visible phosphorescence after long wave UV (see the separate post for an example of this material).
As shown in the photograph above, the fluorite cubes have a yellow color under visible light.
The above gallery images show the specimen under short wave UV (upper left), short wave phosphorescence (upper right), fluorescence under long wave UV (lower left), and long wave phosphorescence (lower right).