Even before you reach for your loupe, a gemmologist needs the right light – as you examine and test a stone, you will need a variety of different lighting conditions to see and properly observe everything that’s going on. Back-lit and diffused lighting is great for peering into a stone’s interior, and a bright spot-light would be perfect for observing optical effects or surface features. And, (did you know?) diamond colour grading must be done under a source of white-light that emits little to no UV light.