GIA DIAMOND ESSENTIALS FINAL 2026
PRACTICE TEST QUESTIONS AND DETAILED
DIAMOND IDENTIFICATION LUMINESCENCE
AND QUALITY ASSESSMENT BREAKDOWN
FULL REVIEW
◉ Culet. Answer: Small facet at the bottom of a finished gem
◉ Durability. Answer: A gemstone's ability to withstand wear, heat,
and chemicals
◉ Facet. Answer: A flat, polished surface on a finished gem
◉ Fancy cut. Answer: Any gemstone shape or cutting style other
than a standard round brilliant
◉ Fire. Answer: The flashes of colour you see in a polished diamond
◉ Four Cs. Answer: Four value factors (clarity, colour, cut, and carat
weight) that describe the quality of a finished gem and also relates
primarily to its value
,◉ Girdle. Answer: The narrow section of a finished gem that forms
the boundary between the crown and the pavilion and functions as
the gem's setting edge
◉ Hardness. Answer: How well a gemstone resists scratches and
abrasion
◉ Inclusion. Answer: Clarity characteristic totally enclosed in a
polished gemstone or extending into it from the surface
◉ Karat. Answer: A unit for the fineness of gold, abbreviated "K" or
"Kt"
◉ Metric carat. Answer: The international unit of measure for gram
weight. One carat equals one-fifth of a gram (0.200g)
◉ Mixed cut. Answer: Cut that combines brilliant-cut and step-cut
styles
◉ Mohs scale. Answer: Ranking of the relative hardness of 10
minerals
◉ Pavilion. Answer: Lower part of a faceted gem below the girdle
, ◉ Point. Answer: One hundredth of a carat (0.01ct)
◉ Scintillation. Answer: The flashes of light and the contrasting dark
areas you see when the diamond, the light, or the observer moves
◉ Simulant. Answer: A natural or manmade material that resembles
a gem (also called imitation)
◉ Single cut. Answer: A round stone with 17 or 18 facets
◉ Stability. Answer: How well a diamond resists chemicals and
temperature changes
◉ Standard round brilliant. Answer: A round brilliant-cut stone with
57 or 58 facets. Often called a full cut
◉ Step cut. Answer: A cutting style that features long narrow facets
in rows parallel to the girdle on both the crown and pavilion
◉ Synthetic gem. Answer: A manmade gem with essentially the
same chemical composition, crystal structure, and properties as a
natural gem
PRACTICE TEST QUESTIONS AND DETAILED
DIAMOND IDENTIFICATION LUMINESCENCE
AND QUALITY ASSESSMENT BREAKDOWN
FULL REVIEW
◉ Culet. Answer: Small facet at the bottom of a finished gem
◉ Durability. Answer: A gemstone's ability to withstand wear, heat,
and chemicals
◉ Facet. Answer: A flat, polished surface on a finished gem
◉ Fancy cut. Answer: Any gemstone shape or cutting style other
than a standard round brilliant
◉ Fire. Answer: The flashes of colour you see in a polished diamond
◉ Four Cs. Answer: Four value factors (clarity, colour, cut, and carat
weight) that describe the quality of a finished gem and also relates
primarily to its value
,◉ Girdle. Answer: The narrow section of a finished gem that forms
the boundary between the crown and the pavilion and functions as
the gem's setting edge
◉ Hardness. Answer: How well a gemstone resists scratches and
abrasion
◉ Inclusion. Answer: Clarity characteristic totally enclosed in a
polished gemstone or extending into it from the surface
◉ Karat. Answer: A unit for the fineness of gold, abbreviated "K" or
"Kt"
◉ Metric carat. Answer: The international unit of measure for gram
weight. One carat equals one-fifth of a gram (0.200g)
◉ Mixed cut. Answer: Cut that combines brilliant-cut and step-cut
styles
◉ Mohs scale. Answer: Ranking of the relative hardness of 10
minerals
◉ Pavilion. Answer: Lower part of a faceted gem below the girdle
, ◉ Point. Answer: One hundredth of a carat (0.01ct)
◉ Scintillation. Answer: The flashes of light and the contrasting dark
areas you see when the diamond, the light, or the observer moves
◉ Simulant. Answer: A natural or manmade material that resembles
a gem (also called imitation)
◉ Single cut. Answer: A round stone with 17 or 18 facets
◉ Stability. Answer: How well a diamond resists chemicals and
temperature changes
◉ Standard round brilliant. Answer: A round brilliant-cut stone with
57 or 58 facets. Often called a full cut
◉ Step cut. Answer: A cutting style that features long narrow facets
in rows parallel to the girdle on both the crown and pavilion
◉ Synthetic gem. Answer: A manmade gem with essentially the
same chemical composition, crystal structure, and properties as a
natural gem
