Refracted light is the light reflected from a diamond’s girdle or facets. It is used to examine slight external and internal flaws in the diamond.
During the process of sorting and examining cut diamonds, dirt and dust are often considered flaws that lower the value of a diamond.
The reflected light shows dirt as scintillation on the diamond’s surface, while actual flaws appear as an integral part of the surface on which it lands. Internal flaws are not seen at all.
