Case Analysis & Practical Application Flashcards

A client submits a diamond that shows a strong green fluorescence under UV and has an unusual color distribution. What treatment should you suspect and how would you confirm it?

Answer: HPHT treatment; confirm with spectroscopic analysis such as DiamondView or FTIR

HPHT treatment can cause unusual UV fluorescence patterns and color anomalies; advanced spectroscopy like DiamondView or FTIR is used to confirm the treatment.

Under magnification, a diamond shows a flash of orange or purple iridescence along a fracture plane. What does this indicate?

Answer: Fracture filling (glass or resin injected to improve clarity appearance)

The 'flash effect'—a distinctive orange or purple iridescence—is the hallmark indicator of fracture filling used to disguise clarity characteristics.

A diamond plots on the border between G and H color. Under what grading condition and technique should the final color determination be made?

Answer: Table-down or pavilion-up against GIA master color comparison diamonds under standardized neutral lighting

GIA color grading is performed with the diamond face-down (pavilion up) under controlled neutral lighting, compared directly against calibrated master comparison diamonds.

A diamond has a body color in the normal D-to-Z range but shows a strong yellow saturation that is face-up visible and attractive. How is this graded?

Answer: If the color is attractive and face-up visible, it may qualify as a Fancy Light Yellow on the fancy color scale

When a diamond's face-up color is both perceptible and attractive, even if the body color technically falls at the Z end, it may be graded as Fancy Light Yellow on the fancy color grading scale.

A near-colorless diamond with strong blue fluorescence is being evaluated for color. Under standard grading conditions, what effect does the fluorescence typically have?

Answer: Under standard grading lighting (non-UV), fluorescence has no impact; grading is based on body color only

GIA color grading is performed under controlled non-UV lighting specifically to isolate body color; fluorescence is noted separately and does not alter the D-to-Z color grade.

A diamond in the H-I color range has a faint brown secondary hue. How does this secondary hue affect its market value compared to a pure H-I stone?

Answer: A brown secondary hue typically reduces value because it diminishes the neutral appearance buyers expect in near-colorless diamonds

A brown secondary hue in any near-colorless grade is generally a value-reducing factor because it detracts from the neutral, crisp appearance associated with those color grades.

A grader assesses the same diamond's color under incandescent light versus daylight-equivalent fluorescent light and gets different impressions. Which light source is correct for GIA D-to-Z color grading?

Answer: Daylight-equivalent fluorescent (approximately 6,500K) lighting, as standardized by GIA

GIA standardizes color grading under daylight-equivalent fluorescent lighting of approximately 6,500K to ensure consistent, reproducible color assessments.