CDG CDG Diamond Treatments & Enhancements 2 — Questions and Answers
Question 1: What does HPHT stand for in the context of diamond treatment?
- High Pressure High Temperature (Correct answer)
- Heat Processing and Hardening Technique
- Hydrogen Pressure Hardening Treatment
- High Purity Heat Treatment
Correct answer: High Pressure High Temperature
HPHT stands for High Pressure High Temperature, a treatment that mimics natural diamond formation conditions to alter color.
Question 2: HPHT treatment is primarily used to accomplish which of the following?
- Improve or change the color of diamonds (Correct answer)
- Increase a diamond's hardness rating
- Remove surface blemishes
- Improve brilliance by polishing internal facets
Correct answer: Improve or change the color of diamonds
HPHT treatment is primarily used to improve or change diamond color, often converting brown or near-colorless stones to colorless or fancy colored.
Question 3: Which spectroscopic method is most reliable for detecting HPHT treatment in diamonds?
- Infrared (FTIR) and UV-Vis spectroscopy (Correct answer)
- X-ray fluorescence (XRF)
- Raman spectroscopy alone
- Visual inspection under magnification
Correct answer: Infrared (FTIR) and UV-Vis spectroscopy
FTIR and UV-Vis spectroscopy reveal characteristic absorption patterns in HPHT-treated diamonds not present in untreated stones.
Question 4: Irradiation treatment of diamonds most commonly produces which colors?
- Blue, green, or fancy yellow (Correct answer)
- Pink or red only
- Colorless
- Brown or cognac
Correct answer: Blue, green, or fancy yellow
Irradiation creates or modifies color centers within the crystal lattice, typically producing blue, green, or fancy yellow colors.
Question 5: What is the primary consumer safety concern with certain irradiation treatment methods?
- Residual radioactivity in some treatment methods (Correct answer)
- Increased brittleness of the stone
- Toxic chemical residue on the surface
- Allergic reactions from the treatment
Correct answer: Residual radioactivity in some treatment methods
Some irradiation methods can leave residual radioactivity in diamonds, requiring monitoring and clearance before sale to consumers.
Question 6: Type IIa diamonds are most commonly targeted for HPHT treatment because they:
- Contain no nitrogen and respond well to color improvement (Correct answer)
- Have the highest fluorescence and need correction
- Are always brown before treatment
- Contain the most inclusions that can be removed
Correct answer: Contain no nitrogen and respond well to color improvement
Type IIa diamonds contain essentially no nitrogen impurities and respond well to HPHT treatment, frequently converting from brownish to colorless.
CDG CDG Diamond Treatments & Enhancements 2
What does HPHT stand for in the context of diamond treatment?