This strong blue fluorescing diamond faces up much better than as seen through the pavilion of the same stone.

Strong blue fluorescence will undoubtedly detract yellow in a diamond. Expect strong blue to hide several color grades in the mounting. It may look like a “G” in the ring and if it turns out to be an “L” when loose on the grading tray, don’t be surprised. The easy solution to this potential problem is a simple check under-long wave ultraviolet light. If it glows blue or a violet blue, you can expect a potential problem with grading. This is not to say that all strong blue-fluorescent diamonds are off color; in fact, many are in the colorless range.