GIA Diamond Grading and Identification 2 — Questions and Answers
Question 1: On the GIA color grading scale, which letter grade represents a truly colorless diamond?
- D (Correct answer)
- F
- G
- H
Correct answer: D
D is the highest color grade on the GIA scale and represents a completely colorless diamond.
Question 2: What does the term 'fluorescence' describe in diamond grading?
- A diamond's reaction to ultraviolet light (Correct answer)
- The sparkle of a diamond under direct sunlight
- The color zoning visible under magnification
- The transparency of the diamond's crystal structure
Correct answer: A diamond's reaction to ultraviolet light
Fluorescence refers to a diamond's visible light emission when exposed to ultraviolet (UV) radiation.
Question 3: Which diamond inclusion type is described as a tiny crystal of another mineral trapped inside the diamond?
- Crystal (Correct answer)
- Feather
- Cloud
- Knot
Correct answer: Crystal
A crystal inclusion is a mineral crystal (which may be another diamond or a different mineral) enclosed within the host diamond.
Question 4: GIA's cut grade for standard round brilliant diamonds evaluates which combination of factors?
- Brightness, fire, and scintillation (Correct answer)
- Color, clarity, and carat weight
- Polish, symmetry, and proportions only
- Table size, girdle thickness, and culet size only
Correct answer: Brightness, fire, and scintillation
GIA's cut grade assesses the overall face-up appearance through brightness, fire, scintillation, as well as design and craftsmanship.
Question 5: A diamond described as 'SI1' on the GIA clarity scale has inclusions that are:
- Noticeable under 10x magnification but not to the naked eye (Correct answer)
- Visible to the naked eye under normal viewing conditions
- Extremely difficult to see even under 10x magnification
- Only visible under 60x magnification
Correct answer: Noticeable under 10x magnification but not to the naked eye
SI1 (Slightly Included 1) inclusions are noticeable under 10x magnification but typically not visible to the unaided eye.
Question 6: What is the standard magnification used by GIA graders to assess diamond clarity?
- 10x (Correct answer)
- 20x
- 30x
- 40x
Correct answer: 10x
GIA uses 10x magnification as the industry standard for evaluating diamond clarity.
Question 7: In GIA grading, what does the term 'table percentage' refer to?
- The table facet width expressed as a percentage of the average girdle diameter (Correct answer)
- The percentage of light that enters through the table facet
- The ratio of the table depth to the total diamond depth
- The number of facets on the table relative to total facets
Correct answer: The table facet width expressed as a percentage of the average girdle diameter
Table percentage is the width of the table facet divided by the average girdle diameter, expressed as a percentage.
GIA Diamond Grading and Identification 2
On the GIA color grading scale, which letter grade represents a truly colorless diamond?