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)
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)
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)
Color center - answer✔✔Structural defect that influences an object's absorption of light and can
cause its color. (Assignment 12)
Conflict diamonds - answer✔✔Diamonds used to finance violence and terror. (Assignment 3)
Consignment - answer✔✔A selection of goods loaned to a dealer by another wholesaler or
manufacturer. (Assignment 20)
Covalent bond - answer✔✔A chemical bond formed by two atoms sharing electrons.
(Assignment 7)
Craftsmanship - answer✔✔The care that goes into the fashioning of a polished diamond, as
confirmed by its finish. (Assignment 15)
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