- Make observations in a darkened environment. Allow a few moments for your eyes to adjust to the darkness in order to be able to detect weak fluorescence.
- Place the stone (s) on a non-reflective background directly under the light source. In order to be sure that the color noted is actually a fluorescent effect, and not a reflection of the Ultraviolet light source from the facets of the stone, always position the stone in several directions.
- Look for a dull powdery color on the surface of the stone (ignore color due to the surface reflection of visible light and from light leaking into the test unit). Record, in both long and short wave ultraviolet light, the reaction of the stone as Inert, Weak, or Strong fluorescence and note the color.
Note: If the stone fluoresces strongly, look for phosphorescence (after-glow).
- Observe the crown, pavilion and girdle of the stone, as it may be a doublet or a triplet.
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