This ultraviolet lamp is very simple to use. It can be an invaluable aid in gem identification and also for detecting some types of treatment.
The ultraviolet lamp, also called a UV lamp, produces a special type of light (actually radiation) called ultraviolet. These lamps are used to reveal the presence or absence of fluorescence in gems. Fluorescence refers to whether or not a stone produces a color reaction when exposed to ultraviolet radiationócolor that is not visible in ordinary lightócolor seen only when the stone is viewed under ultraviolet radiation.
The ultraviolet lamp serves many purposes for the gem identifier. By viewing gems with an ultraviolet lamp in a blackened environment, we are able to see different reactions depending on the gem and, in some cases, an ultraviolet lamp is all we need to determine whether a stone is genuine, an imitation, synthetic, or treated. The use of longwave ultraviolet radiation has proven especially useful for testing emeralds and indicating whether or not they have been oiled. It is also very useful for separating synthetic white spinel and colorless synthetic sapphire, heated blue sapphire and the older Verneuil synthetic blue sapphire. Shortwave radiation is the fastest and easiest way to separate tanzanite from all of the tanzanite imitations currently available.