Gemology Certification Gem Treatments & Enhancements 1 — Questions and Answers
Question 1: What is the most common treatment applied to rubies to improve their color and clarity?
- Fracture filling with lead glass
- Heat treatment (Correct answer)
- Beryllium diffusion
- Irradiation
Correct answer: Heat treatment
Heat treatment is by far the most widely used treatment for rubies, improving color saturation and reducing silk inclusions.
Question 2: Which gemstone is most traditionally treated with cedar oil or synthetic resins to fill surface-reaching fractures?
- Ruby
- Sapphire
- Emerald (Correct answer)
- Tanzanite
Correct answer: Emerald
Emeralds are highly fractured by nature and are routinely treated with oils or resins to improve apparent clarity.
Question 3: Which gemstone is most commonly subjected to irradiation treatment to achieve its popular blue color?
- Ruby
- Blue topaz (Correct answer)
- Tanzanite
- Aquamarine
Correct answer: Blue topaz
Virtually all blue topaz on the market is irradiated and then heat-treated to produce stable blue colors.
Question 4: What does 'untreated' mean when applied to a gemstone in a gemological context?
- The stone has not been cut or polished
- The stone has received no post-mining enhancement beyond cutting and polishing (Correct answer)
- The stone has not been tested in a laboratory
- The stone has not been cleaned or graded
Correct answer: The stone has received no post-mining enhancement beyond cutting and polishing
In gemology, 'untreated' means no enhancement beyond standard cutting and polishing was applied after mining.
Question 5: High-pressure, high-temperature (HPHT) treatment is primarily used on diamonds to improve which characteristic?
- Clarity, by dissolving inclusions
- Color, by reducing or eliminating brownish or yellowish tints (Correct answer)
- Cut precision
- Fluorescence intensity
Correct answer: Color, by reducing or eliminating brownish or yellowish tints
HPHT treatment alters the crystal structure of certain diamonds to improve their color, often converting near-colorless or faint yellow stones toward colorless.
Question 6: Tanzanite found in nature is typically brownish-purple. What treatment transforms it into the prized blue-violet gem seen in the market?
- Fracture filling
- Irradiation
- Heat treatment (Correct answer)
- Beryllium diffusion
Correct answer: Heat treatment
Heat treatment at relatively low temperatures (around 400–500°C) permanently converts brownish tanzanite into the desirable blue-violet color.
Question 7: Which treatment process involves diffusing a foreign element deep into the surface layer of corundum at high temperatures to create an orange or padparadscha-like color?
- Fracture filling
- Irradiation
- Standard heat treatment
- Beryllium diffusion (Correct answer)
Correct answer: Beryllium diffusion
Beryllium diffusion introduces beryllium atoms into the corundum lattice at high temperatures, producing orange, yellow, or padparadscha colors.
Gemology Certification Gem Treatments & Enhancements 1
What is the most common treatment applied to rubies to improve their color and clarity?