[header] How to choose a blue gemstone [title] Look at your gemstones in overhead lighting. [step] Overhead lighting allows for the best viewing, and it will help you see the surface characteristics of the gem. A neutral-colored background will allow you to differentiate between the different shades and intensities of blue. 
By minimizing the visual " noise, " you can focus on the gemstone. [substeps] Despite popular belief, natural light is not always the best light to examine gemstones.