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DIAMONDS & DIAMOND GRADING EXAM
WITH CORRECT ANSWERS.
A series of minute nicks along the facet junctions of a fashioned diamond; gives the edges a white or fuzzy appearance. (Assignment 10) - correct answer- Abrasion (Abr) The highest degree of luster possible in a transparent material. (Assignment 8) - correct answer- Adamantine luster A solid mass of individual, randomly oriented crystals, intergrown or held together by a natural binding agent. (Assignment 7) - correct answer- Aggregate
A deposit where gems are eroded from their source rock, then transported away from the source and further concentrated. (Assignment 5) - correct answer- Alluvial deposit The angle at which a ray of light strikes a surface, measured from the normal. (Assignment 8) - correct answer- Angle of incidence The angle between the normal and a reflected ray of light. (Assignment 8) - correct answer- Angle of reflection Using heat to stabilize irradiated color in gemstones. (Assignment 12) - correct answer- Annealing An estimation of the value of an article, usually for insurance purposes. (Assignment 1) - correct answer- Appraisal The result achieved by adding the smallest and largest girdle measurements of a round brilliant and dividing by two. (Assignment 14) - correct answer- Average girdle diameter
Underground mining that involves building a concrete-lined tunnel under an ore deposit, then collecting the ore through openings in the liner. (Assignment 6) - correct answer- Block caving Placing the first 17 or 18 facets on a diamond. (Assignment 9) - correct answer- Blocking A dark area across the center of an elongated brilliant cut. (Assignment 16) - correct answer- Bow-tie A traditional store consisting of walls and a fixed location. (Assignment 3) - correct answer- Brick-and-mortar retailer The effect of all the diamond's internal and external reflections of white light. (Assignment 8) - correct answer- Brightness A cutting style in which triangular and kite-shaped facets radiate from a gem's center toward its girdle. (Assignment 16) - correct answer- Brilliant cut
Placement and polishing of the star and upper and lower girdle facets. (Assignment 9) - correct answer- Brillianteering A tiny area of impact accompanied by very small, root-like feathers visible at 10X magnification; typically occurs at a facet junction. (Assignment 10) - correct answer- Bruise (Br) Forming the basic face-up outline of a diamond to prepare it for faceting. (Assignment 9) - correct answer- Bruting Large-scale character sampling. (Assignment 5) - correct answer- Bulk sampling 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) - correct answer- Burn Marks (Brn) An angular opening created when part of a feather breaks away. (Assignment 10) - correct answer- Cavity (Cv)
Large, severe, straight break along a plane of atomic weakness; considered an inclusion. (Assignment 10) - correct answer- Cleavage (Cl) Plane parallel to a possible crystal face, where a diamond can split cleanly when struck. (Assignment 7) - correct answer- Cleavage plane 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) - correct answer- Cleaver Dividing a diamond into two or more pieces along a cleavage plane. (Assignment 9) - correct answer- Cleaving Many tightly grouped pinpoints that might be too small to distinguish individually at 10X but together have a hazy appearance. (Assignment 10) - correct answer- Cloud (Cld)
Structural defect that influences an object's absorption of light and can cause its color. (Assignment 12) - correct answer- Color center Diamonds used to finance violence and terror. (Assignment 3) - correct answer- Conflict diamonds A selection of goods loaned to a dealer by another wholesaler or manufacturer. (Assignment 20) - correct answer- Consignment Earth's innermost layer. (Assignment 4) - correct answer- Core A chemical bond formed by two atoms sharing electrons. (Assignment 7) - correct answer- Covalent bond The care that goes into the fashioning of a polished diamond, as confirmed by its finish. (Assignment 15) - correct answer- Craftsmanship
The surface and outermost layer of the earth. (Assignment 4) - correct answer- Crust Solid matter with atoms arranged in a regular, repeating pattern. (Assignment 7) - correct answer- Crystal A mineral crystal contained in a diamond. (Assignment 10) - correct answer- Crystal (Xtl) Internal directions parallel to a mineral's unit cell surfaces. (Assignment 7) - correct answer- Crystal planes Geometric shape of a well-formed crystal. (Assignment 7) - correct answer- Crystal shape (form) Regular, repeating arrangement of atoms in a mineral. (Assignment 7) - correct answer- Crystal structure (lattice) Categories of crystals based on their symmetry and internal structure. (Assignment 7) - correct answer- Crystal systems
Composed of crystals or related to crystals. (Assignment 7) - correct answer- Crystalline The size of the facet at the bottom of the diamond where the pavilion mains meet. (Assignment 15) - correct answer- Culet size Diamond rough with good enough size, shape, clarity, and color to produce a polished stone suitable for use in jewelry. (Assignment 5) - correct answer- Cuttable rough A city, region, or country with a large number of gemstone manufacturers. (Assignment 3) - correct answer- Cutting center The arrangement of a gem's facets. (Assignment 16) - correct answer- Cutting style Lighting of a diamond from the side against a black, non- reflective background. (Assignment 10) - correct answer- Darkfield illumination
Any material that is not diamond or synthetic diamond, but which imitates a diamond's appearance and is used in its place. (Assignment 18) - correct answer- Diamond simulant An independent diamond prospector. (Assignment 2) - correct answer- Digger A weight-retention method where the cutter leaves more girdle thickness to allow for later removal of clarity characteristics around the girdle. (Assignment 14) - correct answer- Digging out 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) - correct answer- Dispersion A holder that secures a diamond during sawing, bruting, or polishing. (Assignment 9) - correct answer- Dop Two separate pieces of material fused or cemented together to form a single assembled stone. (Assignment 18) - correct answer- Doublet
The appearance of double images of a gemstone's facet junctions on the side opposite the viewer. (Assignment 7) - correct answer- Doubling Possessing different physical or optical properties in different crystal directions. (Assignment 7) - correct answer- Doubly refractive (anisotropic) A horizontal tunnel drilled through a diamond pipe. (Assignment
- correct answer- Drift A prospector's term for diamond deposits away from water. (Assignment 2) - correct answer- Dry diggings Business that sells to consumers via television cable, phone line, or satellite. (Assignment 3) - correct answer- Electronic retailer A geologic process that delivers materials (sometimes diamonds) to the surface. (Assignment 4) - correct answer- Emplacement
Any gemstone shape other than round. (Assignment 16) - correct answer- Fancy cut Diamonds that exhibit yellow or brown color beyond the Z range, or that exhibit any other color. (Assignment 12) - correct answer- Fancy-colored diamonds A trade term for any break in a diamond. (Assignment 10) - correct answer- Feather General trade term for a break in a gemstone. Often white and feathery in appearance. (Assignment 10) - correct answer- Feather (Ftr) The quality of the polish and precision of the cut of a fashioned gemstone. (Assignment 15) - correct answer- Finish The flashes of color you see in a polished diamond. (Assignment 8) - correct answer- Fire
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) - correct answer- Flash effect Emission of visible light by a material when it's exposed to ultraviolet radiation. (Assignment 12) - correct answer- Fluorescence Gemstone or simulant with a thin metallic foil or mirroring film applied to its pavilion. (Assignment 18) - correct answer- Foilback Irregular furrow or groove in the surface of a diamond, characteristic of diamond crystals in the gray color range. (Assignment 9) - correct answer- Foss A diamond with the table parallel to a possible cubic face. (Assignment 9) - correct answer- Four-point diamond Treatment that involves injecting a molten glass substance into a diamond's surface-reaching feathers or laser drill-holes. (Assignment 10) - correct answer- Fracture filling
Inclusions or blemishes that establish the clarity grade of a diamond. (Assignment 11) - correct answer- Grade-setting characteristics A small, concentrated area of crystal distortion; can be white or dark, and might appear thread-like or pinpoint-like. (Assignment
- correct answer- Grain Center (GrCnt) Visible, shadow-like lines in a diamond caused by irregularities in the crystal structure. (Assignment 7) - correct answer- Graining (grain lines) Graphite formation around a diamond's mineral inclusions and feathers that results from the extreme conditions of HPHT processing. (Assignment 19) - correct answer- Graphitization Separating heavier materials (diamonds) from a test sample. (Assignment 5) - correct answer- Gravity sorting
An apparatus that uses diamonds' affinity for grease to separate them from other minerals. (Assignment 6) - correct answer- Grease belt Characteristic crystal shape of a specific mineral. (Assignment
- correct answer- Habit The length of time required for half of a group of atoms of a particular type (radioactive) to decay into another type (non- radioactive). (Assignment 19) - correct answer- Half-life Diamond synthesis method that mimics the pressure and temperature conditions that lead to natural diamond formation. (Assignment 19) - correct answer- High pressure, high temperature (HPHT) A category of rocks formed from a molten state. (Assignment 4)
- correct answer- Igneous Diamonds that can be repolished to improve their clarity to a VVS1 or VVS2 grade. (Assignment 17) - correct answer- Improvables
