Diamonds and Diamond Grading GIA
Units 1-5
Absorption spectrum - ANS - A pattern of dark vertical lines or bands shown by certain gems
when viewed through a spectroscope, or a linear graph recorded by a spectrometer.
\Aggregate - ANS - A solid mass of individual randomly oriented crystals, inter grown or held
together by a natural binding agent.
\Alluvial deposits - ANS - A deposit where gems are eroded from their source rock and then
transported away from the source and further concentrated in rivers and streams.
\Appraisal - ANS - An estimation of an article's value, usually for insurance purposes.
\Atom - ANS - the basic structural unit of all matter
\Auction - ANS - A competitive sales process where rough diamonds are sold to the highest
bidder.
\Band gap - ANS - Energy difference between the valence band and the conduction band.
\Beneficiation - ANS - a commitment to reserve a portion of the resources derived from any
country for the economic development of that country
\Bort - ANS - A form of industrial-grade diamond that usually occurs as very included single
crystals in a range of yellows, grays, and browns.
\Bulk sampling - ANS - Large-scale character sampling of 5,000 to 10,000 tons of rock.
\Carbonado - ANS - An aggregate of many randomly oriented interlocking tiny diamond crystals
that is the toughest form of diamond.
\Carbonate - ANS - A class of chemical compounds that contain carbon and oxygen.
\Cave mining - ANS - An underground mining technique in which orebody is drilled beneath the
surface, loosened, and collected as it falls.
\Central Selling Organisation (CSO) - ANS - An agency designed to purchase, sort, evaluate,
and sell rough diamonds
\Character sampling - ANS - Testing the size, shape, clarity, and color of the diamonds in a
deposit based on 500 tons of rock.
\Cleavage - ANS - A smooth, flat break in a crystal parallel to a cleavage plane
\Cleavage Plane - ANS - A planar surface along with a mineral tends to break due to atomic
weakness
\CLIPPIR diamonds - ANS - Cullinan-like, Large, Inclusion-Poor, Pure, Irregular, and Resorbed
diamond.
\Color center - ANS - A defect that can influence an object's absorption of visible light to cause
its color.
\Core - ANS - The earth's innermost layer
\Covalent Bond - ANS - A chemical bond formed when two atoms share electrons
\Cratons - ANS - Large, ancient, stable parts of the earth's
landmasses.
\Crust - ANS - The surface and outermost layer of the earth
, \Crustal diamond - ANS - Rare diamond that forms in the continental crust at or near the earth's
surface due to meteorite impact or tectonic plate collision.
\Crystal Planes - ANS - A set of parallel and evenly spaced planes distributed along certain
crystal directions in which atoms are more closely packed
\Crystal Shape (Form) - ANS - The geometric shape of a well formed crystal (in terms of a
diamond its cubic)
\Crystal Structure (Lattice) - ANS - regular, repeating arrangement of atoms in a mineral
\Crystal Systems - ANS - Categories of crystals based on their symmetry and internal structure-
there are 7 crystal systems- diamonds belong to the cubic or isometric system
\Defect - ANS - An imperfection or deviation from the ideal crystal lattice (three types of defects:
point, line, volume)
\Dense media separation - ANS - A recovery process that separates diamonds from lighter
materials
\Diamond exchange (bourse) - ANS - A membership-based entity that provides service and
venue to facilitate diamond trading.
\Diamond Trading Company (DTC) - ANS - The marketing and sales arm of De Beers (the CSO
was its predecessor).
\Diamond Value Chain - ANS - A sequence of sectors and processes involved in the production
and distribution of diamonds. AKA Diamond Supply Chain
\Doubly refractive (anisotropic) - ANS - Possessing different physical or optical properties in
different crystal directions
\Downstream - ANS - The retail portion of the diamond value chain.
\Drift - ANS - A horizontal tunnel drilled through a diamond pipe.
\Dry diggings - ANS - A prospector's term for diamond deposits away from water
\Eruption - ANS - A geological process that delivers material (sometimes diamonds) to the
surface.
\Gem-quality diamonds - ANS - Diamonds that meet certain criteria to be used as gems in the
jewelry market.
\Geochemical testing - ANS - An analysis that determines the chemical composition of a sample
\Geothermal gradient - ANS - The rate of temperature increase with depth in the earth.
\Glassie - ANS - a well shaped, transparent, octahedral diamond crystal with sharp, square
edges
\Glide plane - ANS - The plane or surface in which a dislocation travels though the crystal to
cause an offset (found in line defects)
\Graining (Grain lines) - ANS - visible, shadow-like lines in a diamond caused by irregularities in
the crystal structure
\Grease belt - ANS - A mechanism that uses diamond's affinity for grease to separate diamonds
from other minerals, usually used in the process of concentrating
\Growth Marks - ANS - Visible features on the surface of a mineral crystal that reflect its internal
growth and development
\Habit - ANS - The characteristic crystal shape or form of a mineral
\How are igneous rocks formed? - ANS - From a molten state: Igneous rock begins in a molten
or partially molten state and becomes solid as it cools.
Units 1-5
Absorption spectrum - ANS - A pattern of dark vertical lines or bands shown by certain gems
when viewed through a spectroscope, or a linear graph recorded by a spectrometer.
\Aggregate - ANS - A solid mass of individual randomly oriented crystals, inter grown or held
together by a natural binding agent.
\Alluvial deposits - ANS - A deposit where gems are eroded from their source rock and then
transported away from the source and further concentrated in rivers and streams.
\Appraisal - ANS - An estimation of an article's value, usually for insurance purposes.
\Atom - ANS - the basic structural unit of all matter
\Auction - ANS - A competitive sales process where rough diamonds are sold to the highest
bidder.
\Band gap - ANS - Energy difference between the valence band and the conduction band.
\Beneficiation - ANS - a commitment to reserve a portion of the resources derived from any
country for the economic development of that country
\Bort - ANS - A form of industrial-grade diamond that usually occurs as very included single
crystals in a range of yellows, grays, and browns.
\Bulk sampling - ANS - Large-scale character sampling of 5,000 to 10,000 tons of rock.
\Carbonado - ANS - An aggregate of many randomly oriented interlocking tiny diamond crystals
that is the toughest form of diamond.
\Carbonate - ANS - A class of chemical compounds that contain carbon and oxygen.
\Cave mining - ANS - An underground mining technique in which orebody is drilled beneath the
surface, loosened, and collected as it falls.
\Central Selling Organisation (CSO) - ANS - An agency designed to purchase, sort, evaluate,
and sell rough diamonds
\Character sampling - ANS - Testing the size, shape, clarity, and color of the diamonds in a
deposit based on 500 tons of rock.
\Cleavage - ANS - A smooth, flat break in a crystal parallel to a cleavage plane
\Cleavage Plane - ANS - A planar surface along with a mineral tends to break due to atomic
weakness
\CLIPPIR diamonds - ANS - Cullinan-like, Large, Inclusion-Poor, Pure, Irregular, and Resorbed
diamond.
\Color center - ANS - A defect that can influence an object's absorption of visible light to cause
its color.
\Core - ANS - The earth's innermost layer
\Covalent Bond - ANS - A chemical bond formed when two atoms share electrons
\Cratons - ANS - Large, ancient, stable parts of the earth's
landmasses.
\Crust - ANS - The surface and outermost layer of the earth
, \Crustal diamond - ANS - Rare diamond that forms in the continental crust at or near the earth's
surface due to meteorite impact or tectonic plate collision.
\Crystal Planes - ANS - A set of parallel and evenly spaced planes distributed along certain
crystal directions in which atoms are more closely packed
\Crystal Shape (Form) - ANS - The geometric shape of a well formed crystal (in terms of a
diamond its cubic)
\Crystal Structure (Lattice) - ANS - regular, repeating arrangement of atoms in a mineral
\Crystal Systems - ANS - Categories of crystals based on their symmetry and internal structure-
there are 7 crystal systems- diamonds belong to the cubic or isometric system
\Defect - ANS - An imperfection or deviation from the ideal crystal lattice (three types of defects:
point, line, volume)
\Dense media separation - ANS - A recovery process that separates diamonds from lighter
materials
\Diamond exchange (bourse) - ANS - A membership-based entity that provides service and
venue to facilitate diamond trading.
\Diamond Trading Company (DTC) - ANS - The marketing and sales arm of De Beers (the CSO
was its predecessor).
\Diamond Value Chain - ANS - A sequence of sectors and processes involved in the production
and distribution of diamonds. AKA Diamond Supply Chain
\Doubly refractive (anisotropic) - ANS - Possessing different physical or optical properties in
different crystal directions
\Downstream - ANS - The retail portion of the diamond value chain.
\Drift - ANS - A horizontal tunnel drilled through a diamond pipe.
\Dry diggings - ANS - A prospector's term for diamond deposits away from water
\Eruption - ANS - A geological process that delivers material (sometimes diamonds) to the
surface.
\Gem-quality diamonds - ANS - Diamonds that meet certain criteria to be used as gems in the
jewelry market.
\Geochemical testing - ANS - An analysis that determines the chemical composition of a sample
\Geothermal gradient - ANS - The rate of temperature increase with depth in the earth.
\Glassie - ANS - a well shaped, transparent, octahedral diamond crystal with sharp, square
edges
\Glide plane - ANS - The plane or surface in which a dislocation travels though the crystal to
cause an offset (found in line defects)
\Graining (Grain lines) - ANS - visible, shadow-like lines in a diamond caused by irregularities in
the crystal structure
\Grease belt - ANS - A mechanism that uses diamond's affinity for grease to separate diamonds
from other minerals, usually used in the process of concentrating
\Growth Marks - ANS - Visible features on the surface of a mineral crystal that reflect its internal
growth and development
\Habit - ANS - The characteristic crystal shape or form of a mineral
\How are igneous rocks formed? - ANS - From a molten state: Igneous rock begins in a molten
or partially molten state and becomes solid as it cools.
