Have you ever seen a diamond that was just plain hazy or perhaps milky? Chances are it contained many separated clouds or one continuous cloud that spreads throughout the stone. Clouds are capable of completely blocking the light required to make a diamond brilliant. Some clouds are so faint they can only be located under high magnification. A cloud is generally made up of very tiny inclusions whose individual crystals or feathers may be identified when viewed under a microscope’s high magnification.
Clouds are a very common occurrence in diamond and can be easily overlooked. By being aware of their existence, you will more readily recognize them when grading. Good light is very important when searching for these ghost-like inclusions and a scope’s dark-field illumination is especially valuable at that point. Most people who overlook clouds are simply rushing the grading process and miss these finer details of a stone’s characteristics.