GIA COLORED STONES COMPREHENSIVE EXAMS
UPDATED QUESTIONS AND ANSWERS SURE A+
✔✔Chemical composition - ✔✔Kinds and relative quantities of atoms that make up a
material.
✔✔Chemical element - ✔✔A substance that consists of atoms of only one kind.
✔✔Chip - ✔✔A damaged area on a gem, usually near the girdle.
✔✔Chrome tourmaline - ✔✔Trade term for a vibrant green tourmaline that's colored by
traces of vanadium, chromium, or both.
✔✔Circled pearl - ✔✔A pearl with one or more grooved or ridged rings all the way
around it.
✔✔Cleavage - ✔✔A smooth, flat break in a gemstone parallel to planes of atomic
weakness, caused by weak or fewer bonds between atoms or both.
✔✔Cloud - ✔✔Any hazy or milky area that cannot be described as a feather, fingerprint,
or group of included crystals or needles.
,✔✔Cobbing - ✔✔Removing heavily included sections from a gemstone rough by
carefully tapping it with a small hammer.
✔✔Color center - ✔✔A small defect in the atomic structure of a material that absorb
light and give rise to a color.
✔✔Color Change - ✔✔A distinct change in gem color under different types of lighting.
✔✔Color range - ✔✔The selection of colors in which a gemstone occurs.
✔✔Color zoning - ✔✔Areas of different color in a gem, caused by variations in growth
conditions.
✔✔Colorless impregnation - ✔✔Filling of pores or other openings with melted wax,
resin, polymer, or plastic to improve appearance and stability.
✔✔Commercial market - ✔✔Market sector where average-quality gemstones are used
in mass-market jewelry.
✔✔Conchiolin - ✔✔The organic "glue" in nacre that holds aragonite platelets together.
✔✔Conchoidal fracture - ✔✔A curved and ridged fracture in a gemstone, extending
from the surface inward.
✔✔Consignment - ✔✔A selection of goods loaned to a dealer by another wholesaler or
gem cutter.
✔✔Contact metamorphism - ✔✔Localized changes caused by an igneous intrusion that
takes place where the magma meets the surrounding rock. New minerals may form due
to temperature changes or introduction of fluids from the magma.
✔✔Core - ✔✔The earth's innermost layer.
✔✔Crazing - ✔✔The network of tiny fractures that develop when opal loses moisture.
✔✔Crown - ✔✔Top part of the gem above the girdle.
✔✔Crown-height to pavilion-depth ratio - ✔✔The relationship of the height of a gem's
crown to the depth of its pavilion, judged by viewing its profile,
✔✔Crust - ✔✔The surface and outermost later of the earth.
✔✔Cryptocystalline - ✔✔An aggregate made up of individual crystals detectable only
under very high magnification.
,✔✔Crystal structure - ✔✔Regular, repeating internal arrangement of atoms in a
material.
✔✔Cultured blister pearl - ✔✔A cultured pearl grown around a nucleus glued under the
mantle tissue inside a mollusk's shell.
✔✔Cultured pearl - ✔✔A pearl formed as the result of human intervention in the
formation process.
✔✔Custom-made jewelry - ✔✔A unique piece designed and created for a particular
customer, often around specially chosen stones.
✔✔Cut - ✔✔A gem dealer's term for a random sample from a parcel of gemstones,
often used to assess the parcel's overall quality.
✔✔Cutter - ✔✔A manufacturer who produces faceted stones, cabochons, or carvings.
✔✔Cutting center - ✔✔A city, region, or country with a large number of gemstone
manufacturers.
✔✔Density - ✔✔How heavy an object is in relation to its size.
✔✔Designer cuts - ✔✔Artistic gem cuts that aren't limited to specific proportions or
shapes.
✔✔Dhun - ✔✔Smoky corundum that turns blue when treated.
✔✔Diffraction - ✔✔A special kind of interference phenomenon that breaks up white light
into spectral hues.
✔✔Disclosure - ✔✔Clearly and accurately informing customer about the nature of the
goods they buy.
✔✔Dopstick - ✔✔Wooden or metal stick that holds the preform during faceting.
✔✔Double refraction - ✔✔When a gem's crystal structure splits light into two rays that
each travel at a slightly different speed and direction.
✔✔Doublet - ✔✔Two separate pieces of material fused oe cemented together to form a
single assembled stone.
✔✔Durability - ✔✔A gemstone's ability to withstand wear, heat, and chemicals.
, ✔✔Dyeing - ✔✔A treatment that adds color or affects color by deepening it, making it
more even, or changing it.
✔✔Eluvial deposit - ✔✔A deposit where gems are eroded from the source rock but
remain in place close to the source.
✔✔Erosion - ✔✔The wearing away and transport of rock materials by natural forces.
✔✔Essence d' orient - ✔✔A mixture of clear varnish and fish scales used in making
imitation pearls.
✔✔Extinction - ✔✔Dark areas in a faceted transparent colored stone.
✔✔Eye clean - ✔✔Description for a gem with no inclusions visible to the unaided eye.
✔✔Facet grade - ✔✔Gemstone rough that's transparent enough and of high enough
quality to produce faceted gems.
✔✔Faceting head - ✔✔Device that holds the dopstick at precise angles to allow correct
orientation during faceting and polishing.
✔✔Fantasy cut - ✔✔A free-form cut that can feature alternating curved and flat
surfaces.
✔✔Feather - ✔✔A general term for a break in a stone.
✔✔Fingerprint - ✔✔Inclusions that forms a pattern that often resembles a human
fingerprint.
✔✔Flame fusion - ✔✔A process in which powdered chemicals are dropped through a
high-temperature flame onto a rotating pedestal to produce a synthetic crystal.
✔✔Floating zone - ✔✔A melt process where a heating unit passes over a rotating solid
rod of chemicals until it forms a synthetic crystal.
✔✔Fluorescence - ✔✔Emission of visible light by a material when it's stimulated by
ultraviolet radiation.
✔✔Flux growth - ✔✔A process in which nutrients dissolve in heated chemicals, then
cool to form synthetic crystals.
✔✔Fracture - ✔✔Any break in a gem other than cleavage or parting.
UPDATED QUESTIONS AND ANSWERS SURE A+
✔✔Chemical composition - ✔✔Kinds and relative quantities of atoms that make up a
material.
✔✔Chemical element - ✔✔A substance that consists of atoms of only one kind.
✔✔Chip - ✔✔A damaged area on a gem, usually near the girdle.
✔✔Chrome tourmaline - ✔✔Trade term for a vibrant green tourmaline that's colored by
traces of vanadium, chromium, or both.
✔✔Circled pearl - ✔✔A pearl with one or more grooved or ridged rings all the way
around it.
✔✔Cleavage - ✔✔A smooth, flat break in a gemstone parallel to planes of atomic
weakness, caused by weak or fewer bonds between atoms or both.
✔✔Cloud - ✔✔Any hazy or milky area that cannot be described as a feather, fingerprint,
or group of included crystals or needles.
,✔✔Cobbing - ✔✔Removing heavily included sections from a gemstone rough by
carefully tapping it with a small hammer.
✔✔Color center - ✔✔A small defect in the atomic structure of a material that absorb
light and give rise to a color.
✔✔Color Change - ✔✔A distinct change in gem color under different types of lighting.
✔✔Color range - ✔✔The selection of colors in which a gemstone occurs.
✔✔Color zoning - ✔✔Areas of different color in a gem, caused by variations in growth
conditions.
✔✔Colorless impregnation - ✔✔Filling of pores or other openings with melted wax,
resin, polymer, or plastic to improve appearance and stability.
✔✔Commercial market - ✔✔Market sector where average-quality gemstones are used
in mass-market jewelry.
✔✔Conchiolin - ✔✔The organic "glue" in nacre that holds aragonite platelets together.
✔✔Conchoidal fracture - ✔✔A curved and ridged fracture in a gemstone, extending
from the surface inward.
✔✔Consignment - ✔✔A selection of goods loaned to a dealer by another wholesaler or
gem cutter.
✔✔Contact metamorphism - ✔✔Localized changes caused by an igneous intrusion that
takes place where the magma meets the surrounding rock. New minerals may form due
to temperature changes or introduction of fluids from the magma.
✔✔Core - ✔✔The earth's innermost layer.
✔✔Crazing - ✔✔The network of tiny fractures that develop when opal loses moisture.
✔✔Crown - ✔✔Top part of the gem above the girdle.
✔✔Crown-height to pavilion-depth ratio - ✔✔The relationship of the height of a gem's
crown to the depth of its pavilion, judged by viewing its profile,
✔✔Crust - ✔✔The surface and outermost later of the earth.
✔✔Cryptocystalline - ✔✔An aggregate made up of individual crystals detectable only
under very high magnification.
,✔✔Crystal structure - ✔✔Regular, repeating internal arrangement of atoms in a
material.
✔✔Cultured blister pearl - ✔✔A cultured pearl grown around a nucleus glued under the
mantle tissue inside a mollusk's shell.
✔✔Cultured pearl - ✔✔A pearl formed as the result of human intervention in the
formation process.
✔✔Custom-made jewelry - ✔✔A unique piece designed and created for a particular
customer, often around specially chosen stones.
✔✔Cut - ✔✔A gem dealer's term for a random sample from a parcel of gemstones,
often used to assess the parcel's overall quality.
✔✔Cutter - ✔✔A manufacturer who produces faceted stones, cabochons, or carvings.
✔✔Cutting center - ✔✔A city, region, or country with a large number of gemstone
manufacturers.
✔✔Density - ✔✔How heavy an object is in relation to its size.
✔✔Designer cuts - ✔✔Artistic gem cuts that aren't limited to specific proportions or
shapes.
✔✔Dhun - ✔✔Smoky corundum that turns blue when treated.
✔✔Diffraction - ✔✔A special kind of interference phenomenon that breaks up white light
into spectral hues.
✔✔Disclosure - ✔✔Clearly and accurately informing customer about the nature of the
goods they buy.
✔✔Dopstick - ✔✔Wooden or metal stick that holds the preform during faceting.
✔✔Double refraction - ✔✔When a gem's crystal structure splits light into two rays that
each travel at a slightly different speed and direction.
✔✔Doublet - ✔✔Two separate pieces of material fused oe cemented together to form a
single assembled stone.
✔✔Durability - ✔✔A gemstone's ability to withstand wear, heat, and chemicals.
, ✔✔Dyeing - ✔✔A treatment that adds color or affects color by deepening it, making it
more even, or changing it.
✔✔Eluvial deposit - ✔✔A deposit where gems are eroded from the source rock but
remain in place close to the source.
✔✔Erosion - ✔✔The wearing away and transport of rock materials by natural forces.
✔✔Essence d' orient - ✔✔A mixture of clear varnish and fish scales used in making
imitation pearls.
✔✔Extinction - ✔✔Dark areas in a faceted transparent colored stone.
✔✔Eye clean - ✔✔Description for a gem with no inclusions visible to the unaided eye.
✔✔Facet grade - ✔✔Gemstone rough that's transparent enough and of high enough
quality to produce faceted gems.
✔✔Faceting head - ✔✔Device that holds the dopstick at precise angles to allow correct
orientation during faceting and polishing.
✔✔Fantasy cut - ✔✔A free-form cut that can feature alternating curved and flat
surfaces.
✔✔Feather - ✔✔A general term for a break in a stone.
✔✔Fingerprint - ✔✔Inclusions that forms a pattern that often resembles a human
fingerprint.
✔✔Flame fusion - ✔✔A process in which powdered chemicals are dropped through a
high-temperature flame onto a rotating pedestal to produce a synthetic crystal.
✔✔Floating zone - ✔✔A melt process where a heating unit passes over a rotating solid
rod of chemicals until it forms a synthetic crystal.
✔✔Fluorescence - ✔✔Emission of visible light by a material when it's stimulated by
ultraviolet radiation.
✔✔Flux growth - ✔✔A process in which nutrients dissolve in heated chemicals, then
cool to form synthetic crystals.
✔✔Fracture - ✔✔Any break in a gem other than cleavage or parting.
