CDG Diamond Grading & Evaluation Techniques 2 — Questions and Answers
Question 1: When using a loupe to grade clarity, at what magnification is the standard GIA grading performed?
- 5x
- 10x (Correct answer)
- 20x
- 30x
Correct answer: 10x
GIA standards require clarity grading under 10x magnification using a properly corrected loupe or microscope.
Question 2: An inclusion that is black or dark and appears as a distinct spot under magnification is most likely which type?
- Crystal
- Cloud
- Carbon spot (black crystal) (Correct answer)
- Feather
Correct answer: Carbon spot (black crystal)
A black crystal, sometimes called a carbon spot, is a dark mineral inclusion visible under magnification and affects clarity grade.
Question 3: Which clarity characteristic describes a small, white, cloud-like grouping of tiny pinpoints that can affect transparency?
- Cavity
- Cloud (Correct answer)
- Needle
- Twinning wisp
Correct answer: Cloud
A cloud is a hazy, diffuse grouping of many tiny pinpoints that collectively can reduce transparency and affect the clarity grade.
Question 4: During clarity grading, a grader notices a fracture that reaches the surface of the diamond. This is classified as a:
- Feather (Correct answer)
- Bruise
- Chip
- Bearding
Correct answer: Feather
A feather is an internal fracture or cleavage that breaks the surface and appears feathery or wispy under magnification.
Question 5: When grading a diamond for clarity, which position provides the best view to detect inclusions near the girdle?
- Table-up, face view
- Pavilion-up, through the culet
- Tilted at 45 degrees (Correct answer)
- Profile view through the girdle
Correct answer: Tilted at 45 degrees
Tilting the diamond at various angles, including 45 degrees, helps reveal inclusions near the girdle that may be hidden in the face-up or face-down positions.
Question 6: A laser drill hole in a diamond is classified under GIA's clarity grading system as:
- A natural inclusion
- An internal clarity characteristic (Correct answer)
- An external blemish
- A transparency feature
Correct answer: An internal clarity characteristic
A laser drill hole is a man-made internal clarity characteristic created to bleach or extract dark inclusions, and it is plotted on the clarity diagram.
Question 7: Which clarity grade range indicates that inclusions are not visible to the naked eye but are noticeable under 10x magnification?
- FL–IF
- VVS1–VVS2
- VS1–VS2 (Correct answer)
- SI1–SI2
Correct answer: VS1–VS2
VS (Very Slightly Included) grades have inclusions that are minor and difficult to see under 10x magnification but are not eye-visible in a standard viewing environment.
CDG Diamond Grading & Evaluation Techniques 2
When using a loupe to grade clarity, at what magnification is the standard GIA grading performed?