GIA Diamonds & Diamond Grading – Exam
Review Guide (2025–2026 Edition) Focus:
Diamond formation, grading criteria, clarity
assessment, color scales, laboratory
evaluation methods.
Diamond Formation & Sources
1. Most natural diamonds form under immense heat and pressure at depths of:
a) The Earth's crust (50-100 km)
b) The Earth's mantle (150-200 km) ✓
c) The Earth's outer core (300-500 km)
d) Volcanic pipes near the surface
2. The primary host rock for commercial diamond deposits is:
a) Kimberlite ✓
b) Lamproite
c) Peridotite
d) Basalt
3. Diamonds are primarily composed of:
a) Silicon Dioxide (SiO2)
b) Carbon (C) ✓
c) Zirconium Silicate (ZrSiO4)
d) Aluminum Oxide (Al2O3)
4. Alluvial diamond deposits are characterized by:
a) Diamonds found in their original volcanic pipe
b) Diamonds that have been transported by water and deposited in riverbeds or oceans
✓
c) Diamonds formed by meteorite impact
d) Diamonds synthesized in a laboratory
5. The oldest known diamonds are approximately how old?
a) 50 million years
, b) 500 million years
c) 1-3 billion years
d) Over 3 billion years ✓
6. A "fancy" colored diamond's color is primarily caused by:
a) Trace elements or structural distortions during formation ✓
b) The presence of numerous inclusions
c) A higher than normal carbon isotope
d) Exposure to radiation after mining
7. The presence of which element causes a diamond to have a yellow color?
a) Boron
b) Hydrogen
c) Nickel
d) Nitrogen ✓
8. The presence of which element causes a diamond to have a blue color?
a) Boron ✓
b) Hydrogen
c) Nickel
d) Nitrogen
9. The geological process that brings diamonds from the mantle to the surface is:
a) Tectonic subduction
b) Deep-source volcanic eruption ✓
c) Glacial movement
d) Seismic liquefaction
10. Which of these is NOT a major source of diamond mining today?
a) Botswana
b) Russia
c) Canada
d) Brazil ✓ (Note: While Brazil produces diamonds, it is not a top-tier producer like the
others.)
The 4Cs & Grading Fundamentals
11. The Four Cs of diamond grading are:
a) Cut, Clarity, Carat, Cost
, b) Color, Clarity, Carat, Crystal
c) Cut, Clarity, Carat, Color ✓
d) Cut, Clarity, Certification, Color
12. A metric carat is defined as:
a) 100 milligrams ✓
b) 200 milligrams
c) 1 gram
d) 5 grams
13. When weighing diamonds, a point represents:
a) 0.01 carat ✓
b) 0.1 carat
c) 1.0 carat
d) 10 carats
14. The GIA D-to-Z color scale is a measure of:
a) The presence of fancy colors
b) The absence of color ✓
c) The level of fluorescence
d) The presence of nitrogen
15. On the GIA clarity scale, which grade represents a "loupe-clean" diamond?
a) Internally Flawless (IF) ✓
b) Very, Very Slightly Included (VVS1)
c) Very Slightly Included (VS1)
d) Flawless (FL)
16. The term "Fluorescence" in a diamond grading report refers to:
a) The diamond's brilliance in sunlight
b) The diamond's reaction to long-wave UV light ✓
c) The diamond's electrical conductivity
d) The diamond's phosphorescence after light exposure
17. The most important C that directly impacts a diamond's brilliance and fire is:
a) Carat Weight
b) Clarity
c) Color
d) Cut ✓
, 18. A diamond's "make" refers to:
a) Its country of origin
b) The quality of its cut proportions and finish ✓
c) The synthetic process used to create it
d) The type of inclusions it contains
19. GIA diamond grading reports are issued for:
a) Natural diamonds only
b) Natural and treated diamonds only
c) Natural, treated, and synthetic diamonds ✓
d) Only diamonds over 1 carat
20. The primary purpose of a diamond grading report is to:
a) Provide a monetary appraisal
b) Describe key characteristics and quality factors in a consistent, unbiased manner ✓
c) Certify the diamond's country of origin
d) Guarantee the diamond's investment value
Clarity Grading
21. An inclusion is defined as:
a) A surface blemish
b) An internal characteristic ✓
c) A polish line
d) A type of crystal
22. A characteristic that breaks the surface of a polished diamond is called a:
a) Feather
b) Cavity
c) Internal Grain Line
d) Blemish ✓
23. The standard magnification used for determining a final clarity grade is:
a) 10x ✓
b) 20x
c) 30x
d) 40x
Review Guide (2025–2026 Edition) Focus:
Diamond formation, grading criteria, clarity
assessment, color scales, laboratory
evaluation methods.
Diamond Formation & Sources
1. Most natural diamonds form under immense heat and pressure at depths of:
a) The Earth's crust (50-100 km)
b) The Earth's mantle (150-200 km) ✓
c) The Earth's outer core (300-500 km)
d) Volcanic pipes near the surface
2. The primary host rock for commercial diamond deposits is:
a) Kimberlite ✓
b) Lamproite
c) Peridotite
d) Basalt
3. Diamonds are primarily composed of:
a) Silicon Dioxide (SiO2)
b) Carbon (C) ✓
c) Zirconium Silicate (ZrSiO4)
d) Aluminum Oxide (Al2O3)
4. Alluvial diamond deposits are characterized by:
a) Diamonds found in their original volcanic pipe
b) Diamonds that have been transported by water and deposited in riverbeds or oceans
✓
c) Diamonds formed by meteorite impact
d) Diamonds synthesized in a laboratory
5. The oldest known diamonds are approximately how old?
a) 50 million years
, b) 500 million years
c) 1-3 billion years
d) Over 3 billion years ✓
6. A "fancy" colored diamond's color is primarily caused by:
a) Trace elements or structural distortions during formation ✓
b) The presence of numerous inclusions
c) A higher than normal carbon isotope
d) Exposure to radiation after mining
7. The presence of which element causes a diamond to have a yellow color?
a) Boron
b) Hydrogen
c) Nickel
d) Nitrogen ✓
8. The presence of which element causes a diamond to have a blue color?
a) Boron ✓
b) Hydrogen
c) Nickel
d) Nitrogen
9. The geological process that brings diamonds from the mantle to the surface is:
a) Tectonic subduction
b) Deep-source volcanic eruption ✓
c) Glacial movement
d) Seismic liquefaction
10. Which of these is NOT a major source of diamond mining today?
a) Botswana
b) Russia
c) Canada
d) Brazil ✓ (Note: While Brazil produces diamonds, it is not a top-tier producer like the
others.)
The 4Cs & Grading Fundamentals
11. The Four Cs of diamond grading are:
a) Cut, Clarity, Carat, Cost
, b) Color, Clarity, Carat, Crystal
c) Cut, Clarity, Carat, Color ✓
d) Cut, Clarity, Certification, Color
12. A metric carat is defined as:
a) 100 milligrams ✓
b) 200 milligrams
c) 1 gram
d) 5 grams
13. When weighing diamonds, a point represents:
a) 0.01 carat ✓
b) 0.1 carat
c) 1.0 carat
d) 10 carats
14. The GIA D-to-Z color scale is a measure of:
a) The presence of fancy colors
b) The absence of color ✓
c) The level of fluorescence
d) The presence of nitrogen
15. On the GIA clarity scale, which grade represents a "loupe-clean" diamond?
a) Internally Flawless (IF) ✓
b) Very, Very Slightly Included (VVS1)
c) Very Slightly Included (VS1)
d) Flawless (FL)
16. The term "Fluorescence" in a diamond grading report refers to:
a) The diamond's brilliance in sunlight
b) The diamond's reaction to long-wave UV light ✓
c) The diamond's electrical conductivity
d) The diamond's phosphorescence after light exposure
17. The most important C that directly impacts a diamond's brilliance and fire is:
a) Carat Weight
b) Clarity
c) Color
d) Cut ✓
, 18. A diamond's "make" refers to:
a) Its country of origin
b) The quality of its cut proportions and finish ✓
c) The synthetic process used to create it
d) The type of inclusions it contains
19. GIA diamond grading reports are issued for:
a) Natural diamonds only
b) Natural and treated diamonds only
c) Natural, treated, and synthetic diamonds ✓
d) Only diamonds over 1 carat
20. The primary purpose of a diamond grading report is to:
a) Provide a monetary appraisal
b) Describe key characteristics and quality factors in a consistent, unbiased manner ✓
c) Certify the diamond's country of origin
d) Guarantee the diamond's investment value
Clarity Grading
21. An inclusion is defined as:
a) A surface blemish
b) An internal characteristic ✓
c) A polish line
d) A type of crystal
22. A characteristic that breaks the surface of a polished diamond is called a:
a) Feather
b) Cavity
c) Internal Grain Line
d) Blemish ✓
23. The standard magnification used for determining a final clarity grade is:
a) 10x ✓
b) 20x
c) 30x
d) 40x
