GIA Diamond Treatments and Synthetics 3 — Questions and Answers
Question 1: Which of the following treatments is considered permanent and stable under normal wearing conditions?
- Fracture filling with glass
- Laser drilling (Correct answer)
- Coating with a colored film
- Clarity enhancement with resins
Correct answer: Laser drilling
Laser drilling creates a permanent tunnel in the diamond and cannot be reversed, unlike fracture filling which can be damaged by heat or chemicals.
Question 2: A HPHT synthetic diamond produced by the flux method is most likely to contain which microscopic feature?
- Gas bubbles in a circular pattern
- Metallic flux inclusions appearing opaque and reflective (Correct answer)
- Needle-like rutile inclusions
- Fingerprint-shaped liquid inclusions
Correct answer: Metallic flux inclusions appearing opaque and reflective
Flux-grown HPHT synthetics frequently contain metallic inclusions (iron-nickel or cobalt) from the flux solvent, which appear opaque and strongly reflective under magnification.
Question 3: When examining a diamond with shortwave UV light, a fracture-filled stone may show:
- Inert reaction across the entire stone
- Yellow-green fluorescence in the filled fracture only (Correct answer)
- Strong blue fluorescence throughout
- Chalky white fluorescence in the filler material
Correct answer: Yellow-green fluorescence in the filled fracture only
The glass-like filler used in fracture filling often fluoresces yellow-green under shortwave UV, which can help identify treated areas.
Question 4: The term 'diamond simulant' differs from 'synthetic diamond' in that a simulant:
- Is grown in a laboratory environment
- Has the same chemical composition as diamond
- Imitates diamond's appearance but has different chemistry (Correct answer)
- Can only be identified by professional gemologists
Correct answer: Imitates diamond's appearance but has different chemistry
A simulant (e.g., moissanite, CZ) looks similar to diamond but has different chemical composition, while a synthetic diamond is chemically identical to natural diamond.
Question 5: Which observation under a standard gemological microscope most strongly suggests a diamond has been fracture-filled?
- Presence of naturals along the girdle
- Flow lines or trapped gas bubbles within a feather (Correct answer)
- Bearding along the girdle edge
- Internal graining in the pavilion
Correct answer: Flow lines or trapped gas bubbles within a feather
Flow lines and trapped gas bubbles visible within a fracture are telltale signs of the glass-like filler injected during fracture filling treatment.
Question 6: GIA reports for fracture-filled diamonds differ from standard Diamond Grading Reports in that they:
- Do not assign a color grade
- Note that clarity grade applies to the stone as it exists with the treatment (Correct answer)
- Refuse to assign a clarity grade altogether
- Are issued on a different colored document
Correct answer: Note that clarity grade applies to the stone as it exists with the treatment
GIA will grade fracture-filled diamonds but notes on the report that the clarity grade reflects the stone as treated, warning that the treatment may affect durability.
Question 7: A pink diamond suspected of being irradiation-treated would show which spectroscopic feature absent in a natural pink diamond?
- H2 defect center at 986 nm
- 3H center at 503.2 nm induced by irradiation (Correct answer)
- N3 center at 415 nm
- Boron absorption in the infrared
Correct answer: 3H center at 503.2 nm induced by irradiation
The 3H center at 503.2 nm is a radiation-induced defect that appears in irradiated diamonds and is not found in naturally colored pink diamonds.
GIA Diamond Treatments and Synthetics 3
Which of the following treatments is considered permanent and stable under normal wearing conditions?