Diamond & Diamond Grading Exam
Abrasion (Abr) - Answer-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 - Answer-The highest degree of luster possible in a transparent material.
(Assignment 8)
Aggregate - Answer-A solid mass of individual, randomly oriented crystals, intergrown or held together
by a natural binding agent. (Assignment 7)
Alluvial deposit - Answer-A deposit where gems are eroded from their source rock, then transported
away from the source and further concentrated. (Assignment 5)
Angle of incidence - Answer-The angle at which a ray of light strikes a surface, measured from the
normal. (Assignment 8)
Angle of reflection - Answer-The angle between the normal and a reflected ray of light. (Assignment 8)
Annealing - Answer-Using heat to stabilize irradiated color in gemstones. (Assignment 12)
,Appraisal - Answer-An estimation of the value of an article, usually for insurance purposes. (Assignment
1)
Average girdle diameter - Answer-The result achieved by adding the smallest and largest girdle
measurements of a round brilliant and dividing by two. (Assignment 14)
Bast - Answer-Frosted rough diamond. "Bark" in Dutch. (Assignment 9)
Bearded Girdle (BG) - Answer-Very small feathers that extend from the girdle surface into the stone;
can result from the cutting process. (Assignment 10)
Belly - Answer-The slightly curving center of the long side of a pear, marquise, heart, or oval.
(Assignment 16)
Beneficiation - Answer-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) - Answer-De Beers' formalized commitment of itself and its sightholders
to the highest ethical standards. (Assignment 3)
Blemish - Answer-Clarity characteristic that's confined to the surface of a polished gemstone.
(Assignment 10)
Block caving - Answer-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 - Answer-Placing the first 17 or 18 facets on a diamond. (Assignment 9)
,Bow-tie - Answer-A dark area across the center of an elongated brilliant cut. (Assignment 16)
Brick-and-mortar retailer - Answer-A traditional store consisting of walls and a fixed location.
(Assignment 3)
Brightness - Answer-The effect of all the diamond's internal and external reflections of white light.
(Assignment 8)
Brilliant cut - Answer-A cutting style in which triangular and kite-shaped facets radiate from a gem's
center toward its girdle. (Assignment 16)
Brillianteering - Answer-Placement and polishing of the star and upper and lower girdle facets.
(Assignment 9)
Bruise (Br) - Answer-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 - Answer-Forming the basic face-up outline of a diamond to prepare it for faceting. (Assignment
9)
Bulk sampling - Answer-Large-scale character sampling. (Assignment 5)
Burn Marks (Brn) - Answer-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) - Answer-An angular opening created when part of a feather breaks away. (Assignment 10)
Central Selling Organisation (CSO) - Answer-An agency designed to purchase, sort, evaluate, and sell
rough diamonds. (Assignment 2)
, Character sampling - Answer-Testing for the size, shape, clarity, and color of the diamonds in a deposit.
(Assignment 5)
Characteristic color - Answer-The basic color of a fancy-colored diamond. (Assignment 13)
Chemical vapor deposition (CVD) - Answer-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) - Answer-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 - Answer-Internal or external feature of a gemstone that helps determine its
quality and establish its identity. (Assignment 10)
Cleavage (Cl) - Answer-Large, severe, straight break along a plane of atomic weakness; considered an
inclusion. (Assignment 10)
Cleavage plane - Answer-Plane parallel to a possible crystal face, where a diamond can split cleanly
when struck. (Assignment 7)
Cleaver - Answer-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 - Answer-Dividing a diamond into two or more pieces along a cleavage plane. (Assignment 9)
Cloud (Cld) - Answer-Many tightly grouped pinpoints that might be too small to distinguish individually
at 10X but together have a hazy appearance. (Assignment 10)
Abrasion (Abr) - Answer-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 - Answer-The highest degree of luster possible in a transparent material.
(Assignment 8)
Aggregate - Answer-A solid mass of individual, randomly oriented crystals, intergrown or held together
by a natural binding agent. (Assignment 7)
Alluvial deposit - Answer-A deposit where gems are eroded from their source rock, then transported
away from the source and further concentrated. (Assignment 5)
Angle of incidence - Answer-The angle at which a ray of light strikes a surface, measured from the
normal. (Assignment 8)
Angle of reflection - Answer-The angle between the normal and a reflected ray of light. (Assignment 8)
Annealing - Answer-Using heat to stabilize irradiated color in gemstones. (Assignment 12)
,Appraisal - Answer-An estimation of the value of an article, usually for insurance purposes. (Assignment
1)
Average girdle diameter - Answer-The result achieved by adding the smallest and largest girdle
measurements of a round brilliant and dividing by two. (Assignment 14)
Bast - Answer-Frosted rough diamond. "Bark" in Dutch. (Assignment 9)
Bearded Girdle (BG) - Answer-Very small feathers that extend from the girdle surface into the stone;
can result from the cutting process. (Assignment 10)
Belly - Answer-The slightly curving center of the long side of a pear, marquise, heart, or oval.
(Assignment 16)
Beneficiation - Answer-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) - Answer-De Beers' formalized commitment of itself and its sightholders
to the highest ethical standards. (Assignment 3)
Blemish - Answer-Clarity characteristic that's confined to the surface of a polished gemstone.
(Assignment 10)
Block caving - Answer-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 - Answer-Placing the first 17 or 18 facets on a diamond. (Assignment 9)
,Bow-tie - Answer-A dark area across the center of an elongated brilliant cut. (Assignment 16)
Brick-and-mortar retailer - Answer-A traditional store consisting of walls and a fixed location.
(Assignment 3)
Brightness - Answer-The effect of all the diamond's internal and external reflections of white light.
(Assignment 8)
Brilliant cut - Answer-A cutting style in which triangular and kite-shaped facets radiate from a gem's
center toward its girdle. (Assignment 16)
Brillianteering - Answer-Placement and polishing of the star and upper and lower girdle facets.
(Assignment 9)
Bruise (Br) - Answer-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 - Answer-Forming the basic face-up outline of a diamond to prepare it for faceting. (Assignment
9)
Bulk sampling - Answer-Large-scale character sampling. (Assignment 5)
Burn Marks (Brn) - Answer-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) - Answer-An angular opening created when part of a feather breaks away. (Assignment 10)
Central Selling Organisation (CSO) - Answer-An agency designed to purchase, sort, evaluate, and sell
rough diamonds. (Assignment 2)
, Character sampling - Answer-Testing for the size, shape, clarity, and color of the diamonds in a deposit.
(Assignment 5)
Characteristic color - Answer-The basic color of a fancy-colored diamond. (Assignment 13)
Chemical vapor deposition (CVD) - Answer-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) - Answer-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 - Answer-Internal or external feature of a gemstone that helps determine its
quality and establish its identity. (Assignment 10)
Cleavage (Cl) - Answer-Large, severe, straight break along a plane of atomic weakness; considered an
inclusion. (Assignment 10)
Cleavage plane - Answer-Plane parallel to a possible crystal face, where a diamond can split cleanly
when struck. (Assignment 7)
Cleaver - Answer-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 - Answer-Dividing a diamond into two or more pieces along a cleavage plane. (Assignment 9)
Cloud (Cld) - Answer-Many tightly grouped pinpoints that might be too small to distinguish individually
at 10X but together have a hazy appearance. (Assignment 10)
