UV lamp output variation can significantly affect the fluorescence colour and intensity observed in diamond. This device utilises a very stable, narrowband UV LED (365 nm) whose output will not fluctuate over time compared to traditional mercury-based UV lamps. Fluorescence is an important factor in gem identification, and the GIA® UV Lamp and Viewing Cabinet provides the same evaluation environment used by GIA and includes a compact viewing enclosure and calibrated references for the intensity of blue fluorescence in diamond.