4Cs of Diamond Quality Flashcards

Which of the following inclusions in a diamond is most likely to raise concerns about structural integrity?

Answer: A large feather extending to the surface

A feather (fracture) that extends to the surface can be a vulnerability point where the diamond may chip or cleave under impact.

GIA grades diamond color by comparing the stone to a set of reference stones called:

Answer: GIA master color comparison diamonds

GIA grades diamond color by comparing the unknown stone face-down to a set of master color comparison diamonds with known grades.

What does the term 'fire' mean when GIA evaluates cut quality?

Answer: The dispersion of light into the colors of the spectrum

Fire refers to the dispersion of light into the spectral colors — the rainbow flashes — seen in a well-cut diamond.

A round brilliant diamond has a girdle graded 'extremely thin.' This is significant because:

Answer: It makes the girdle vulnerable to chipping during setting or wear

An extremely thin girdle is fragile and prone to chipping, especially during the setting process or from everyday knocks.

Which of the following statements about carat weight is TRUE?

Answer: Carat weight measures mass, not size or dimensions

Carat is a unit of mass (200 mg per carat); the face-up size depends on cut proportions and shape, not carat weight alone.

The GIA Gemological Institute grading report for a diamond lists clarity as 'SI1.' A customer asks if the inclusions are eye-visible. The correct response is:

Answer: Typically no — SI1 inclusions are generally not visible to the unaided eye

SI1 (Slightly Included 1) inclusions are noticeable under 10x magnification but are typically not visible to the unaided eye.

Which 4C has the GREATEST impact on a diamond's brilliance and light performance?

Answer: Cut

Cut has the greatest impact on brilliance because even a colorless, flawless diamond will appear dull if its proportions and facets are poorly executed.