Diamond & Diamond Grading Exam 2023;everything you
need to pass is here
Abrasion (Abr)
A series of minute nicks along the facet junctions of a fashioned diamond; gives the
edges a white or fuzzy appearance. (Assignment 10)
Adamantine luster
The highest degree of luster possible in a transparent material. (Assignment 8)
Aggregate
A solid mass of individual, randomly oriented crystals, intergrown or held together by a
natural binding agent. (Assignment 7)
Alluvial deposit
A deposit where gems are eroded from their source rock, then transported away from
the source and further concentrated. (Assignment 5)
Angle of incidence
The angle at which a ray of light strikes a surface, measured from the normal.
(Assignment 8)
Angle of reflection
The angle between the normal and a reflected ray of light. (Assignment 8)
Annealing
Using heat to stabilize irradiated color in gemstones. (Assignment 12)
Appraisal
An estimation of the value of an article, usually for insurance purposes. (Assignment 1)
Average girdle diameter
The result achieved by adding the smallest and largest girdle measurements of a round
brilliant and dividing by two. (Assignment 14)
Bast
Frosted rough diamond. "Bark" in Dutch. (Assignment 9)
Bearded Girdle (BG)
Very small feathers that extend from the girdle surface into the stone; can result from
the cutting process. (Assignment 10)
Belly
The slightly curving center of the long side of a pear, marquise, heart, or oval.
(Assignment 16)
Beneficiation
A commitment to reserve a portion of the resources derived from any country for the
economic development of that country. (Assignment 3)
Best Practices Principles (BPP)
De Beers' formalized commitment of itself and its sightholders to the highest ethical
standards. (Assignment 3)
Blemish
Clarity characteristic that's confined to the surface of a polished gemstone. (Assignment
10)
Block caving
,Underground mining that involves building a concrete-lined tunnel under an ore deposit,
then collecting the ore through openings in the liner. (Assignment 6)
Blocking
Placing the first 17 or 18 facets on a diamond. (Assignment 9)
Bow-tie
A dark area across the center of an elongated brilliant cut. (Assignment 16)
Brick-and-mortar retailer
A traditional store consisting of walls and a fixed location. (Assignment 3)
Brightness
The effect of all the diamond's internal and external reflections of white light.
(Assignment 8)
Brilliant cut
A cutting style in which triangular and kite-shaped facets radiate from a gem's center
toward its girdle. (Assignment 16)
Brillianteering
Placement and polishing of the star and upper and lower girdle facets. (Assignment 9)
Bruise (Br)
A tiny area of impact accompanied by very small, root-like feathers visible at 10X
magnification; typically occurs at a facet junction. (Assignment 10)
Bruting
Forming the basic face-up outline of a diamond to prepare it for faceting. (Assignment 9)
Bulk sampling
Large-scale character sampling. (Assignment 5)
Burn Marks (Brn)
Hazy surface areas that result from excessive heat or from uneven polishing caused by
structural irregularities; also called polish marks or burned facets. (Assignment 10)
Cavity (Cv)
An angular opening created when part of a feather breaks away. (Assignment 10)
Central Selling Organisation (CSO)
An agency designed to purchase, sort, evaluate, and sell rough diamonds. (Assignment
2)
Character sampling
Testing for the size, shape, clarity, and color of the diamonds in a deposit. (Assignment
5)
Characteristic color
The basic color of a fancy-colored diamond. (Assignment 13)
Chemical vapor deposition (CVD)
An industrial process adapted to allow growth of synthetic diamond from carbon-rich
gas in thin layers onto a silicon or diamond surface. (Assignment 19)
Chip (Ch)
A shallow opening caused by damage to the stone's surface; typically occurs at a girdle
edge, facet junction, or culet. (Assignment 10)
Clarity characteristic
Internal or external feature of a gemstone that helps determine its quality and establish
its identity. (Assignment 10)
Cleavage (Cl)
, Large, severe, straight break along a plane of atomic weakness; considered an
inclusion. (Assignment 10)
Cleavage plane
Plane parallel to a possible crystal face, where a diamond can split cleanly when struck.
(Assignment 7)
Cleaver
A person who cleaves, or splits, a diamond along a cleavage plane. The cleaver might
also be responsible for planning the fashioning of a polished gem. (Assignment 9)
Cleaving
Dividing a diamond into two or more pieces along a cleavage plane. (Assignment 9)
Cloud (Cld)
Many tightly grouped pinpoints that might be too small to distinguish individually at 10X
but together have a hazy appearance. (Assignment 10)
Color center
Structural defect that influences an object's absorption of light and can cause its color.
(Assignment 12)
Conflict diamonds
Diamonds used to finance violence and terror. (Assignment 3)
Consignment
A selection of goods loaned to a dealer by another wholesaler or manufacturer.
(Assignment 20)
Core
Earth's innermost layer. (Assignment 4)
Covalent bond
A chemical bond formed by two atoms sharing electrons. (Assignment 7)
Craftsmanship
The care that goes into the fashioning of a polished diamond, as confirmed by its finish.
(Assignment 15)
Cratons
Ancient, large, and stable parts of the earth's continental crust. (Assignment 4)
Critical angle
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
A person who performs the cross-working operations during diamond polishing;
sometimes called a cross cutter. (Assignment 9)
Cross working
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
The angle formed by the bezel facets and the girdle plane. (Assignment 14)
Crown height percentage
The distance from the girdle plane to the table, expressed as a percentage of average
girdle diameter. (Assignment 14)
Crust
The surface and outermost layer of the earth. (Assignment 4)
need to pass is here
Abrasion (Abr)
A series of minute nicks along the facet junctions of a fashioned diamond; gives the
edges a white or fuzzy appearance. (Assignment 10)
Adamantine luster
The highest degree of luster possible in a transparent material. (Assignment 8)
Aggregate
A solid mass of individual, randomly oriented crystals, intergrown or held together by a
natural binding agent. (Assignment 7)
Alluvial deposit
A deposit where gems are eroded from their source rock, then transported away from
the source and further concentrated. (Assignment 5)
Angle of incidence
The angle at which a ray of light strikes a surface, measured from the normal.
(Assignment 8)
Angle of reflection
The angle between the normal and a reflected ray of light. (Assignment 8)
Annealing
Using heat to stabilize irradiated color in gemstones. (Assignment 12)
Appraisal
An estimation of the value of an article, usually for insurance purposes. (Assignment 1)
Average girdle diameter
The result achieved by adding the smallest and largest girdle measurements of a round
brilliant and dividing by two. (Assignment 14)
Bast
Frosted rough diamond. "Bark" in Dutch. (Assignment 9)
Bearded Girdle (BG)
Very small feathers that extend from the girdle surface into the stone; can result from
the cutting process. (Assignment 10)
Belly
The slightly curving center of the long side of a pear, marquise, heart, or oval.
(Assignment 16)
Beneficiation
A commitment to reserve a portion of the resources derived from any country for the
economic development of that country. (Assignment 3)
Best Practices Principles (BPP)
De Beers' formalized commitment of itself and its sightholders to the highest ethical
standards. (Assignment 3)
Blemish
Clarity characteristic that's confined to the surface of a polished gemstone. (Assignment
10)
Block caving
,Underground mining that involves building a concrete-lined tunnel under an ore deposit,
then collecting the ore through openings in the liner. (Assignment 6)
Blocking
Placing the first 17 or 18 facets on a diamond. (Assignment 9)
Bow-tie
A dark area across the center of an elongated brilliant cut. (Assignment 16)
Brick-and-mortar retailer
A traditional store consisting of walls and a fixed location. (Assignment 3)
Brightness
The effect of all the diamond's internal and external reflections of white light.
(Assignment 8)
Brilliant cut
A cutting style in which triangular and kite-shaped facets radiate from a gem's center
toward its girdle. (Assignment 16)
Brillianteering
Placement and polishing of the star and upper and lower girdle facets. (Assignment 9)
Bruise (Br)
A tiny area of impact accompanied by very small, root-like feathers visible at 10X
magnification; typically occurs at a facet junction. (Assignment 10)
Bruting
Forming the basic face-up outline of a diamond to prepare it for faceting. (Assignment 9)
Bulk sampling
Large-scale character sampling. (Assignment 5)
Burn Marks (Brn)
Hazy surface areas that result from excessive heat or from uneven polishing caused by
structural irregularities; also called polish marks or burned facets. (Assignment 10)
Cavity (Cv)
An angular opening created when part of a feather breaks away. (Assignment 10)
Central Selling Organisation (CSO)
An agency designed to purchase, sort, evaluate, and sell rough diamonds. (Assignment
2)
Character sampling
Testing for the size, shape, clarity, and color of the diamonds in a deposit. (Assignment
5)
Characteristic color
The basic color of a fancy-colored diamond. (Assignment 13)
Chemical vapor deposition (CVD)
An industrial process adapted to allow growth of synthetic diamond from carbon-rich
gas in thin layers onto a silicon or diamond surface. (Assignment 19)
Chip (Ch)
A shallow opening caused by damage to the stone's surface; typically occurs at a girdle
edge, facet junction, or culet. (Assignment 10)
Clarity characteristic
Internal or external feature of a gemstone that helps determine its quality and establish
its identity. (Assignment 10)
Cleavage (Cl)
, Large, severe, straight break along a plane of atomic weakness; considered an
inclusion. (Assignment 10)
Cleavage plane
Plane parallel to a possible crystal face, where a diamond can split cleanly when struck.
(Assignment 7)
Cleaver
A person who cleaves, or splits, a diamond along a cleavage plane. The cleaver might
also be responsible for planning the fashioning of a polished gem. (Assignment 9)
Cleaving
Dividing a diamond into two or more pieces along a cleavage plane. (Assignment 9)
Cloud (Cld)
Many tightly grouped pinpoints that might be too small to distinguish individually at 10X
but together have a hazy appearance. (Assignment 10)
Color center
Structural defect that influences an object's absorption of light and can cause its color.
(Assignment 12)
Conflict diamonds
Diamonds used to finance violence and terror. (Assignment 3)
Consignment
A selection of goods loaned to a dealer by another wholesaler or manufacturer.
(Assignment 20)
Core
Earth's innermost layer. (Assignment 4)
Covalent bond
A chemical bond formed by two atoms sharing electrons. (Assignment 7)
Craftsmanship
The care that goes into the fashioning of a polished diamond, as confirmed by its finish.
(Assignment 15)
Cratons
Ancient, large, and stable parts of the earth's continental crust. (Assignment 4)
Critical angle
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
A person who performs the cross-working operations during diamond polishing;
sometimes called a cross cutter. (Assignment 9)
Cross working
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
The angle formed by the bezel facets and the girdle plane. (Assignment 14)
Crown height percentage
The distance from the girdle plane to the table, expressed as a percentage of average
girdle diameter. (Assignment 14)
Crust
The surface and outermost layer of the earth. (Assignment 4)
