Why are diamonds treated?At the turn of the 20th century, scientists began experimenting with advanced diamond treatments, which were created for two primary reasons—to alter color or to improve clarity. These methods include coating, HPHT color treatment, laser drilling and fracture-filling. As science has advanced, treatments have become more sophisticated and harder to detect.
New coatings can turn diamonds virtually any color, as illustrated by these ~0.40 ct coated diamonds. Photo: GIA
What is diamond coating?
Coating is when a diamond is covered with an ultra-thin layer of chemicals or plastics to mask the diamond’s original color and increase the attractiveness of the diamond’s color. For example, blue coating on a yellowish diamond can neutralize its bodycolor and make the diamond appear more colorless. The ultra-thin coating is usually only applied to the pavilion or girdle region of a diamond and can be difficult to detect. It will scratch and wear off over time, however, and can be damaged by heat. Because this treatment is not permanent.