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What is the UV test on gemstones?
Ultraviolet fluorescence is used by gemologists, jewelers, and collectors to separate artificial gemstones from real, ones or in determining if the gemstone has been heat-treated. A Spectro-UV UV light can be used on a large sample of stones, saving time and money.
A Warning About Ultraviolet Testing
Never look at your ultraviolet (UV) light. Shortwave (SW) UV light can damage your eyes, even to the point of blindness. If you’re ever unsure if your UV light source is on, check the switch. Better yet, a flame-fusion ruby will tell you instantly if the light is on or not. (All rubies fluoresce, but these synthetic rubies fluoresce very strongly).
Ultraviolet Testing Tools
Just beyond the visible light spectrum lies infrared and UV light. For gem identification, we use longwave (LW) light, 315 to 400 nm, and SW light, 200 to 280 nm. The range in between isn’t used.
For gem testing purposes, you need lights that will show the LW and SW independently of each other.