DIAMOND & DIAMOND GRADING EXAM QUESTIONS
AND ANSWERS LATEST 2025/2026
Covalent bond - ANS-A chemical bond formed by two atoms sharing electrons.
(Assignment 7)
Craftsmanship - ANS-The care that goes into the fashioning of a polished diamond, as
confirmed by its finish. (Assignment 15)
Cratons - ANS-Ancient, large, and stable parts of the earth's continental crust.
(Assignment 4)
Critical angle - ANS-Angle between the normal and the maximum angle of refraction,
which is the largest angle at which rays inside the diamond can escape. (Assignment 8)
Cross worker - ANS-A person who performs the cross-working operations during
diamond polishing; sometimes called a cross cutter. (Assignment 9)
Cross working - ANS-Placing the bezel and pavilion facets on round and fancy shapes.
Sometimes combined with blocking, especially on smaller stones. Also called cross
cutting. (Assignment 9)
Crown angle - ANS-The angle formed by the bezel facets and the girdle plane.
(Assignment 14)
Crown height percentage - ANS-The distance from the girdle plane to the table,
expressed as a percentage of average girdle diameter. (Assignment 14)
Crust - ANS-The surface and outermost layer of the earth. (Assignment 4)
Crystal - ANS-Solid matter with atoms arranged in a regular, repeating pattern.
(Assignment 7)
Crystal (Xtl) - ANS-A mineral crystal contained in a diamond. (Assignment 10)
Crystal planes - ANS-Internal directions parallel to a mineral's unit cell surfaces.
(Assignment 7)
Crystal shape (form) - ANS-Geometric shape of a well-formed crystal. (Assignment 7)
,Crystal structure (lattice) - ANS-Regular, repeating arrangement of atoms in a mineral.
(Assignment 7)
Crystal systems - ANS-Categories of crystals based on their symmetry and internal
structure. (Assignment 7)
Crystalline - ANS-Composed of crystals or related to crystals. (Assignment 7)
Culet size - ANS-The size of the facet at the bottom of the diamond where the pavilion
mains meet. (Assignment 15)
Cuttable rough - ANS-Diamond rough with good enough size, shape, clarity, and color
to produce a polished stone suitable for use in jewelry. (Assignment 5)
Cutting center - ANS-A city, region, or country with a large number of gemstone
manufacturers. (Assignment 3)
Cutting style - ANS-The arrangement of a gem's facets. (Assignment 16)
Darkfield illumination - ANS-Lighting of a diamond from the side against a black, non-
reflective background. (Assignment 10)
Dense media separation - ANS-A recovery process that separates diamonds from
lighter material. Also called heavy media separation. (Assignment 6)
Depth of field - ANS-The distance that's clear and sharp above and below a point you
focus on with a magnifier. (Assignment 10)
Design - ANS-A diamond's physical shape, including its proportions and durability,
determined by decisions made during the fashioning process. (Assignment 15)
Diamantaire - ANS-A knowledgeable, experienced, and successful person, usually a
dealer or manufacturer, in the diamond trade. (Assignment 20)
Diamond pipeline - ANS-The path diamonds followed from the mine to the consumer.
(Assignment 2)
Diamond simulant - ANS-Any material that is not diamond or synthetic diamond, but
which imitates a diamond's appearance and is used in its place. (Assignment 18)
Digger - ANS-An independent diamond prospector. (Assignment 2)
,Digging out - ANS-A weight-retention method where the cutter leaves more girdle
thickness to allow for later removal of clarity characteristics around the girdle.
(Assignment 14)
Dispersion - ANS-An optical property that's the difference between the RI values of
specific violet and red wavelengths of visible light for a given material. (Assignment 8)
Dop - ANS-A holder that secures a diamond during sawing, bruting, or polishing.
(Assignment 9)
Doublet - ANS-Two separate pieces of material fused or cemented together to form a
single assembled stone. (Assignment 18)
Doubling - ANS-The appearance of double images of a gemstone's facet junctions on
the side opposite the viewer. (Assignment 7)
Doubly refractive (anisotropic) - ANS-Possessing different physical or optical properties
in different crystal directions. (Assignment 7)
Drift - ANS-A horizontal tunnel drilled through a diamond pipe. (Assignment 6)
Dry diggings - ANS-A prospector's term for diamond deposits away from water.
(Assignment 2)
Electronic retailer - ANS-Business that sells to consumers via television cable, phone
line, or satellite. (Assignment 3)
Emplacement - ANS-A geologic process that delivers materials (sometimes diamonds)
to the surface. (Assignment 4)
Etch Channels - ANS-Angular openings that start at the surface of the diamond and
extend into it, often with striations perpendicular to their length; considered inclusions.
(Assignment 10)
Extra Facet (EF) - ANS-A small facet that's not required by the cutting style, placed
without regard for the diamond's symmetry; most often found near the girdle.
(Assignment 10)
Eye-visible - ANS-Visible to the unaided eye, without magnification. (Assignment 11)
Face-down (or table-down) - ANS-A position that orients a gemstone's pavilion toward
the viewer. (Assignment 13)
, Face-up - ANS-A position that orients a gemstone's crown facets and table toward the
viewer. (Assignment 10)
Face-up (or table-up) - ANS-A position that orients a gemstone's crown toward the
viewer. (Assignment 13)
Fancy cut - ANS-Any gemstone shape other than round. (Assignment 16)
Fancy-colored diamonds - ANS-Diamonds that exhibit yellow or brown color beyond the
Z range, or that exhibit any other color. (Assignment 12)
Feather - ANS-A trade term for any break in a diamond. (Assignment 10)
Feather (Ftr) - ANS-General trade term for a break in a gemstone. Often white and
feathery in appearance. (Assignment 10)
Finish - ANS-The quality of the polish and precision of the cut of a fashioned gemstone.
(Assignment 15)
Fire - ANS-The flashes of color you see in a polished diamond. (Assignment 8)
Flash effect - ANS-A flash of changing color seen in a fracture-filled diamond when you
look parallel to the filled inclusion and rock the diamond back and forth under
magnification. (Assignment 10)
Fluorescence - ANS-Emission of visible light by a material when it's exposed to
ultraviolet radiation. (Assignment 12)
Foilback - ANS-Gemstone or simulant with a thin metallic foil or mirroring film applied to
its pavilion. (Assignment 18)
Foss - ANS-Irregular furrow or groove in the surface of a diamond, characteristic of
diamond crystals in the gray color range. (Assignment 9)
Four-point diamond - ANS-A diamond with the table parallel to a possible cubic face.
(Assignment 9)
Fracture filling - ANS-Treatment that involves injecting a molten glass substance into a
diamond's surface-reaching feathers or laser drill-holes. (Assignment 10)
French tips - ANS-A faceting style that replaces the large bezel facets at the points of
AND ANSWERS LATEST 2025/2026
Covalent bond - ANS-A chemical bond formed by two atoms sharing electrons.
(Assignment 7)
Craftsmanship - ANS-The care that goes into the fashioning of a polished diamond, as
confirmed by its finish. (Assignment 15)
Cratons - ANS-Ancient, large, and stable parts of the earth's continental crust.
(Assignment 4)
Critical angle - ANS-Angle between the normal and the maximum angle of refraction,
which is the largest angle at which rays inside the diamond can escape. (Assignment 8)
Cross worker - ANS-A person who performs the cross-working operations during
diamond polishing; sometimes called a cross cutter. (Assignment 9)
Cross working - ANS-Placing the bezel and pavilion facets on round and fancy shapes.
Sometimes combined with blocking, especially on smaller stones. Also called cross
cutting. (Assignment 9)
Crown angle - ANS-The angle formed by the bezel facets and the girdle plane.
(Assignment 14)
Crown height percentage - ANS-The distance from the girdle plane to the table,
expressed as a percentage of average girdle diameter. (Assignment 14)
Crust - ANS-The surface and outermost layer of the earth. (Assignment 4)
Crystal - ANS-Solid matter with atoms arranged in a regular, repeating pattern.
(Assignment 7)
Crystal (Xtl) - ANS-A mineral crystal contained in a diamond. (Assignment 10)
Crystal planes - ANS-Internal directions parallel to a mineral's unit cell surfaces.
(Assignment 7)
Crystal shape (form) - ANS-Geometric shape of a well-formed crystal. (Assignment 7)
,Crystal structure (lattice) - ANS-Regular, repeating arrangement of atoms in a mineral.
(Assignment 7)
Crystal systems - ANS-Categories of crystals based on their symmetry and internal
structure. (Assignment 7)
Crystalline - ANS-Composed of crystals or related to crystals. (Assignment 7)
Culet size - ANS-The size of the facet at the bottom of the diamond where the pavilion
mains meet. (Assignment 15)
Cuttable rough - ANS-Diamond rough with good enough size, shape, clarity, and color
to produce a polished stone suitable for use in jewelry. (Assignment 5)
Cutting center - ANS-A city, region, or country with a large number of gemstone
manufacturers. (Assignment 3)
Cutting style - ANS-The arrangement of a gem's facets. (Assignment 16)
Darkfield illumination - ANS-Lighting of a diamond from the side against a black, non-
reflective background. (Assignment 10)
Dense media separation - ANS-A recovery process that separates diamonds from
lighter material. Also called heavy media separation. (Assignment 6)
Depth of field - ANS-The distance that's clear and sharp above and below a point you
focus on with a magnifier. (Assignment 10)
Design - ANS-A diamond's physical shape, including its proportions and durability,
determined by decisions made during the fashioning process. (Assignment 15)
Diamantaire - ANS-A knowledgeable, experienced, and successful person, usually a
dealer or manufacturer, in the diamond trade. (Assignment 20)
Diamond pipeline - ANS-The path diamonds followed from the mine to the consumer.
(Assignment 2)
Diamond simulant - ANS-Any material that is not diamond or synthetic diamond, but
which imitates a diamond's appearance and is used in its place. (Assignment 18)
Digger - ANS-An independent diamond prospector. (Assignment 2)
,Digging out - ANS-A weight-retention method where the cutter leaves more girdle
thickness to allow for later removal of clarity characteristics around the girdle.
(Assignment 14)
Dispersion - ANS-An optical property that's the difference between the RI values of
specific violet and red wavelengths of visible light for a given material. (Assignment 8)
Dop - ANS-A holder that secures a diamond during sawing, bruting, or polishing.
(Assignment 9)
Doublet - ANS-Two separate pieces of material fused or cemented together to form a
single assembled stone. (Assignment 18)
Doubling - ANS-The appearance of double images of a gemstone's facet junctions on
the side opposite the viewer. (Assignment 7)
Doubly refractive (anisotropic) - ANS-Possessing different physical or optical properties
in different crystal directions. (Assignment 7)
Drift - ANS-A horizontal tunnel drilled through a diamond pipe. (Assignment 6)
Dry diggings - ANS-A prospector's term for diamond deposits away from water.
(Assignment 2)
Electronic retailer - ANS-Business that sells to consumers via television cable, phone
line, or satellite. (Assignment 3)
Emplacement - ANS-A geologic process that delivers materials (sometimes diamonds)
to the surface. (Assignment 4)
Etch Channels - ANS-Angular openings that start at the surface of the diamond and
extend into it, often with striations perpendicular to their length; considered inclusions.
(Assignment 10)
Extra Facet (EF) - ANS-A small facet that's not required by the cutting style, placed
without regard for the diamond's symmetry; most often found near the girdle.
(Assignment 10)
Eye-visible - ANS-Visible to the unaided eye, without magnification. (Assignment 11)
Face-down (or table-down) - ANS-A position that orients a gemstone's pavilion toward
the viewer. (Assignment 13)
, Face-up - ANS-A position that orients a gemstone's crown facets and table toward the
viewer. (Assignment 10)
Face-up (or table-up) - ANS-A position that orients a gemstone's crown toward the
viewer. (Assignment 13)
Fancy cut - ANS-Any gemstone shape other than round. (Assignment 16)
Fancy-colored diamonds - ANS-Diamonds that exhibit yellow or brown color beyond the
Z range, or that exhibit any other color. (Assignment 12)
Feather - ANS-A trade term for any break in a diamond. (Assignment 10)
Feather (Ftr) - ANS-General trade term for a break in a gemstone. Often white and
feathery in appearance. (Assignment 10)
Finish - ANS-The quality of the polish and precision of the cut of a fashioned gemstone.
(Assignment 15)
Fire - ANS-The flashes of color you see in a polished diamond. (Assignment 8)
Flash effect - ANS-A flash of changing color seen in a fracture-filled diamond when you
look parallel to the filled inclusion and rock the diamond back and forth under
magnification. (Assignment 10)
Fluorescence - ANS-Emission of visible light by a material when it's exposed to
ultraviolet radiation. (Assignment 12)
Foilback - ANS-Gemstone or simulant with a thin metallic foil or mirroring film applied to
its pavilion. (Assignment 18)
Foss - ANS-Irregular furrow or groove in the surface of a diamond, characteristic of
diamond crystals in the gray color range. (Assignment 9)
Four-point diamond - ANS-A diamond with the table parallel to a possible cubic face.
(Assignment 9)
Fracture filling - ANS-Treatment that involves injecting a molten glass substance into a
diamond's surface-reaching feathers or laser drill-holes. (Assignment 10)
French tips - ANS-A faceting style that replaces the large bezel facets at the points of
