GIA DIAMONDS AND DIAMOND GRADING EXAM QUESTIONS AND
ANSWERS - 100% VERIFIED - LATEST 2026 /2027 GUARANTEED PASS
Q: What does GIA stand for? ANSWER Gemological Institute of America.
Q: Who founded GIA? ANSWER Robert M. Shipley.
Q: When was GIA founded? ANSWER 1931.
Q: What is the GIA's mission? ANSWER To protect all buyers and sellers of
gemstones by setting and maintaining the standard for diamond grading.
Q: What are the "4Cs" of diamond grading? ANSWER Carat, Color, Clarity, and
Cut.
Q: What is a diamond's chemical composition? ANSWER Pure carbon (C).
Q: What is the crystal system of a diamond? ANSWER Cubic (isometric).
Q: What is the refractive index (RI) of diamond? ANSWER 2.417.
Q: What is diamond's dispersion? ANSWER 0.044.
Q: What is the hardness of diamond on the Mohs scale? ANSWER 10.
Q: Where are most diamonds mined? ANSWER Russia, Botswana, Canada,
Democratic Republic of Congo, Australia, and South Africa.
Q: What is a "paragenesis" diamond? ANSWER A diamond formed in the
earth's mantle.
Q: What is kimberlite? ANSWER An igneous rock that is the primary host for
diamonds.
Q: What is lamproite? ANSWER Another type of igneous rock that can
transport diamonds to the surface.
Q: How old are most natural diamonds? ANSWER Between 1 billion and 3.5
billion years old.
Q: What is an "allotrope"? ANSWER Different structural forms of the same
element; diamond and graphite are allotropes of carbon.
,Q: What causes a diamond's brilliance? ANSWER Total internal reflection and
high refractive index.
Q: What causes a diamond's fire? ANSWER Dispersion, which separates white
light into spectral colors.
Q: What is the specific gravity of diamond? ANSWER 3.52.
Q: Are diamonds conductive? ANSWER Natural diamonds are generally
electrical insulators, but some blue diamonds (boron-bearing) are
semiconductors.
Q: What is a diamond's cleavage direction? ANSWER Perfect octahedral.
Q: What does "tenacity" mean in gemology? ANSWER A mineral's resistance
to breaking; diamond has good tenacity but can be shattered by a blow along
its cleavage plane.
Q: What is the typical temperature of diamond formation? ANSWER Between
900°C and 1,300°C.
Q: What is the typical depth of diamond formation? ANSWER Between 140
and 190 kilometers (87 to 118 miles) in the mantle.
Q: What is a "macle" in diamond rough? ANSWER A flattened, triangular
twinned crystal.
Q: What is an "octahedron"? ANSWER The most common crystal shape for
natural diamonds (two pyramids joined at the base).
Q: What is a "dodecahedron" in diamond terms? ANSWER A 12-sided diamond
crystal shape.
Q: What is a "cube" in diamond terms? ANSWER A less common 6-sided
diamond crystal shape.
Q: What is the difference between a diamond and a gemstone? ANSWER
Diamond is a specific gemstone made of carbon; "gemstone" is a broad
category for any mineral/organic material used in jewelry.
Q: What tool is essential for basic diamond grading? ANSWER A 10x loupe.
PART 2: CARAT WEIGHT (31-60)
31. Q: What is a "carat"? ANSWER A unit of weight equal to 200 milligrams
(0.2 grams).
, 32. Q: Where does the word "carat" originate? ANSWER From the carob seeds
historically used to balance scales.
33. Q: How many "points" are in one carat? ANSWER 100 points.
34. Q: What does a 0.50 ct diamond weigh in points? ANSWER 50 points.
35. Q: What is a "grain" in diamond weighing? ANSWER A historical unit equal
to 0.25 carats (25 points).
36. Q: Does carat weight equal physical size? ANSWER No, cut proportions
affect the spread (millimeter dimensions) of a diamond.
37. Q: What is "magic size" in diamonds? ANSWER Weights like 0.50, 0.75,
1.00 ct where price per carat jumps significantly.
38. Q: What is "face-up size"? ANSWER The millimeter diameter of the
diamond as viewed from the top.
39. Q: What formula estimates the weight of a round brilliant diamond?
ANSWER Diameter x Diameter x Depth x 0.0061.
40. Q: What formula estimates the weight of an oval diamond? ANSWER
Length x Width x Depth x 0.0062.
41. Q: What formula estimates the weight of a pear shape diamond? ANSWER
Length x Width x Depth x 0.0060.
42. Q: What formula estimates the weight of a marquise diamond? ANSWER
Length x Width x Depth x 0.0057.
43. Q: What formula estimates the weight of an emerald cut diamond?
ANSWER Length x Width x Depth x 0.0080 (adjustments needed for bulge).
44. Q: What is a "melee" diamond? ANSWER A small diamond, typically
weighing under 0.20 carats.
45. Q: What is "star" melee? ANSWER Very small melee diamonds, usually
under 0.02 carats.
46. Q: How are melee diamonds typically sold? ANSWER By parcel, according
to their total weight.
47. Q: Does a 2.00 ct diamond cost twice as much as a 1.00 ct diamond of the
same quality? ANSWER No, it costs significantly more per carat because larger
diamonds are rarer.
ANSWERS - 100% VERIFIED - LATEST 2026 /2027 GUARANTEED PASS
Q: What does GIA stand for? ANSWER Gemological Institute of America.
Q: Who founded GIA? ANSWER Robert M. Shipley.
Q: When was GIA founded? ANSWER 1931.
Q: What is the GIA's mission? ANSWER To protect all buyers and sellers of
gemstones by setting and maintaining the standard for diamond grading.
Q: What are the "4Cs" of diamond grading? ANSWER Carat, Color, Clarity, and
Cut.
Q: What is a diamond's chemical composition? ANSWER Pure carbon (C).
Q: What is the crystal system of a diamond? ANSWER Cubic (isometric).
Q: What is the refractive index (RI) of diamond? ANSWER 2.417.
Q: What is diamond's dispersion? ANSWER 0.044.
Q: What is the hardness of diamond on the Mohs scale? ANSWER 10.
Q: Where are most diamonds mined? ANSWER Russia, Botswana, Canada,
Democratic Republic of Congo, Australia, and South Africa.
Q: What is a "paragenesis" diamond? ANSWER A diamond formed in the
earth's mantle.
Q: What is kimberlite? ANSWER An igneous rock that is the primary host for
diamonds.
Q: What is lamproite? ANSWER Another type of igneous rock that can
transport diamonds to the surface.
Q: How old are most natural diamonds? ANSWER Between 1 billion and 3.5
billion years old.
Q: What is an "allotrope"? ANSWER Different structural forms of the same
element; diamond and graphite are allotropes of carbon.
,Q: What causes a diamond's brilliance? ANSWER Total internal reflection and
high refractive index.
Q: What causes a diamond's fire? ANSWER Dispersion, which separates white
light into spectral colors.
Q: What is the specific gravity of diamond? ANSWER 3.52.
Q: Are diamonds conductive? ANSWER Natural diamonds are generally
electrical insulators, but some blue diamonds (boron-bearing) are
semiconductors.
Q: What is a diamond's cleavage direction? ANSWER Perfect octahedral.
Q: What does "tenacity" mean in gemology? ANSWER A mineral's resistance
to breaking; diamond has good tenacity but can be shattered by a blow along
its cleavage plane.
Q: What is the typical temperature of diamond formation? ANSWER Between
900°C and 1,300°C.
Q: What is the typical depth of diamond formation? ANSWER Between 140
and 190 kilometers (87 to 118 miles) in the mantle.
Q: What is a "macle" in diamond rough? ANSWER A flattened, triangular
twinned crystal.
Q: What is an "octahedron"? ANSWER The most common crystal shape for
natural diamonds (two pyramids joined at the base).
Q: What is a "dodecahedron" in diamond terms? ANSWER A 12-sided diamond
crystal shape.
Q: What is a "cube" in diamond terms? ANSWER A less common 6-sided
diamond crystal shape.
Q: What is the difference between a diamond and a gemstone? ANSWER
Diamond is a specific gemstone made of carbon; "gemstone" is a broad
category for any mineral/organic material used in jewelry.
Q: What tool is essential for basic diamond grading? ANSWER A 10x loupe.
PART 2: CARAT WEIGHT (31-60)
31. Q: What is a "carat"? ANSWER A unit of weight equal to 200 milligrams
(0.2 grams).
, 32. Q: Where does the word "carat" originate? ANSWER From the carob seeds
historically used to balance scales.
33. Q: How many "points" are in one carat? ANSWER 100 points.
34. Q: What does a 0.50 ct diamond weigh in points? ANSWER 50 points.
35. Q: What is a "grain" in diamond weighing? ANSWER A historical unit equal
to 0.25 carats (25 points).
36. Q: Does carat weight equal physical size? ANSWER No, cut proportions
affect the spread (millimeter dimensions) of a diamond.
37. Q: What is "magic size" in diamonds? ANSWER Weights like 0.50, 0.75,
1.00 ct where price per carat jumps significantly.
38. Q: What is "face-up size"? ANSWER The millimeter diameter of the
diamond as viewed from the top.
39. Q: What formula estimates the weight of a round brilliant diamond?
ANSWER Diameter x Diameter x Depth x 0.0061.
40. Q: What formula estimates the weight of an oval diamond? ANSWER
Length x Width x Depth x 0.0062.
41. Q: What formula estimates the weight of a pear shape diamond? ANSWER
Length x Width x Depth x 0.0060.
42. Q: What formula estimates the weight of a marquise diamond? ANSWER
Length x Width x Depth x 0.0057.
43. Q: What formula estimates the weight of an emerald cut diamond?
ANSWER Length x Width x Depth x 0.0080 (adjustments needed for bulge).
44. Q: What is a "melee" diamond? ANSWER A small diamond, typically
weighing under 0.20 carats.
45. Q: What is "star" melee? ANSWER Very small melee diamonds, usually
under 0.02 carats.
46. Q: How are melee diamonds typically sold? ANSWER By parcel, according
to their total weight.
47. Q: Does a 2.00 ct diamond cost twice as much as a 1.00 ct diamond of the
same quality? ANSWER No, it costs significantly more per carat because larger
diamonds are rarer.
