CDG Diamond Treatments & Enhancements Flashcards

What substance is most commonly used in fracture filling of diamonds?

Answer: Lead glass (high lead-content glass)

Lead glass is the most common fracture-filling material because its refractive index closely matches that of diamond, making the filled fractures nearly invisible.

Which of the following is the most telltale sign of fracture filling when viewed under magnification?

Answer: Rainbow flash effect (iridescent color flash)

The iridescent flash effect — typically orange-pink or blue-purple — at the fracture plane is the most characteristic indicator of fracture filling under magnification.

How does fracture filling affect a diamond's apparent clarity grade?

Answer: It can improve the apparent clarity by several grades

Fracture filling conceals fractures, potentially making a diamond appear several clarity grades higher than its actual untreated grade.

Which organization requires disclosure of fracture filling and will not grade treated diamonds on standard reports?

Answer: GIA (Gemological Institute of America)

GIA requires disclosure of fracture filling and will not issue standard grading reports for clarity-enhanced diamonds, as consumer transparency is mandatory.

What happens to fracture-filled diamonds when exposed to heat during jewelry repair?

Answer: The filler can melt, boil, or be expelled, damaging the treatment

Heat from soldering or repair can melt or expel the lead-glass filler, permanently damaging the treatment and potentially harming the diamond itself.

Fracture filling in diamonds is best detected using which lighting technique?

Answer: Darkfield illumination combined with fiber-optic lighting

Darkfield illumination combined with fiber-optic lighting most effectively reveals the flash effect and other indicators of fracture filling.