Shown here is a pretty nice specimen of corundum var. ruby from the Mundarara Mine, Longido District, Arusha Region, Tanzania. Its fluorescence is not very bright, but it is a beautiful, deep saturated red. Just bright enough for a display, if placed closer to the lamp.
Size: 7,5 cm X 6,3 cm X 2,8 cm
Shown below: Longwave UV fluorescence, then specimen in visible light.
Longwave UV response
Specimen shown in visible light.