CDG Diamond Treatments & Enhancements Flashcards

What is the purpose of laser drilling in diamond treatment?

Answer: To reach dark inclusions and remove or bleach them

Laser drilling creates a narrow channel to reach dark inclusions, which are then bleached with acid or left as a less visible whitish feature.

How does KM (Kiduah Meyuchad) drilling differ from traditional laser drilling?

Answer: It creates a surface-reaching fracture rather than a straight drill hole

KM drilling creates a surface-reaching fracture that reaches the inclusion without leaving a straight drill hole, making it harder to detect than traditional laser drilling.

Diamond coatings are most often applied to improve which characteristic?

Answer: Color appearance by masking a yellowish tint

Thin film coatings applied to the girdle or pavilion are used to mask yellowish tints and improve the apparent color grade of lower-quality diamonds.

How can a gemologist best detect a coating on a diamond's surface?

Answer: Examining the girdle area under high magnification for uneven film or abrasion marks

High magnification examination of the girdle reveals coating irregularities, thickness variations, or abrasion marks where the coating has worn away.

Which clarity characteristic type CANNOT be improved through laser drilling?

Answer: White feathers or clouds

Laser drilling targets high-contrast dark inclusions, so white feathers or clouds — which are already low-contrast — offer no benefit from the procedure.

When a grading report states 'clarity enhanced,' what is the grader obligated to do?

Answer: Grade the diamond as it appears after enhancement and fully disclose the treatment

The grader must disclose all clarity enhancements on the report; the grade reflects the treated stone's current appearance per GIA and industry standards.