GIA COLORED STONES EVALUATION 2026 TEST
QUESTIONS AND ANSWERS SURE A+
✔✔Mantle convection - ✔✔Circulation in the mantle that drives the movement of the
earth's plates.
✔✔Mantle-tissue piece - ✔✔A small square of mantle tissue cut from a donor mollusk
and implanted in a host mollusk with or without a bead.
✔✔Matching tray - ✔✔A grooved, neutrally colored, non-reflective tray, used to match
sets of stones.
✔✔Melt process - ✔✔A synthetic-crystal growth method in which the chemical mixture
is melted, then recrystallized.
✔✔Memo - ✔✔Buying agreement where a dealer entrusts merchandise to a client for
inspection and approval without requiring immediate payment.
✔✔Metamict - ✔✔A mineral that's been broken down from a crystalline to a partly
amorphous state by emanations from radioactive impurities .
✔✔Metamorphic rock - ✔✔Rock altered by heat and pressure, or by heated fluids from
magma.
,✔✔Metric carat - ✔✔The international unit of measurement for gem weight. ( 1 carat
equals 0.20 gram )
✔✔Microcrystalline - ✔✔An aggregate made up of individual crystals visible under
magnification.
✔✔Middle market - ✔✔Market sector where better-quality gemstones are used in well-
finished, moderately priced jewelry pieces.
✔✔Milk and honey - ✔✔a two-toned effect seen when a chatoyant gem is positioned at
right angles to a light source.
✔✔Mine lot (mine run) - ✔✔A mixture of gem qualities that represents unsorted
production from a particular mine.
✔✔Mineral - ✔✔A natural, inorganic substance with a characteristic chemical
composition and usually characteristic structure.
✔✔Mixed cut - ✔✔A cutting style that contains brilliant-cut and step-cut facets.
✔✔Mother-of-pearl - ✔✔The nacreous layer inside a pearl-bearing mollusk's shell.
✔✔Mottling - ✔✔An uneven distribution of color against a contrasting background.
✔✔Mountain jade - ✔✔Thick-skinned jadeite boulders.
✔✔Nacre - ✔✔The natural substance produced by pearl-bearing mollusk's shell.
✔✔Natural gem - ✔✔Gems produced by natural processes, without human help.
✔✔Natural pearl - ✔✔A pearl that forms without human assistance.
✔✔Needle - ✔✔A long, thin inclusion that can be a solid crystal or a hollow tube that
might be filled with a liquid or gas
✔✔Negative crystal - ✔✔An angular, hollow space within a gem that resembles a
mineral inclusion.
✔✔New mine - ✔✔The colored texture category of jadeite.
✔✔Old mine - ✔✔The finest texture category of jadeite.
✔✔Optic axis - ✔✔Direction of single refraction in a doubly refractive gem.
,✔✔Organic - ✔✔Produced by, or derived from, a living organism.
✔✔Orient - ✔✔Iridescence seen in some natural cultured pearls and mother-of-pearl.
✔✔Origin - ✔✔The geographical place where a gem was mined.
✔✔Oxidizing environment - ✔✔An oxygen-rich environment that surrounds a gem
during heat treatment, causing it to absorb oxygen.
✔✔Paraiba tourmaline - ✔✔Trade term for rare, expensive, vibrant green to blue or
violet elbaite tourmaline, originally found only in Brazil's Paraiba state.
✔✔Parcel - ✔✔A quantity of stones, sometimes of similar size and quality, perhaps from
a single mine, but often from various sources, that's offered for sale together.
✔✔Parti-colored - ✔✔Gems that show color zoning with two or more colors.
✔✔Parting - ✔✔A flat break in a gemstone caused by concentrated included minerals
parallel to a twinning plane.
✔✔Pavilion - ✔✔Lower part of a faceted gem below the girdle.
✔✔Pearl - ✔✔A nacreous, organic gem formed in the body of a mollusk.
✔✔Pearl sac - ✔✔Tissue that encloses an implanted bead nucleus and mantle-tissue
piece, or the piece alone, and secretes nacre to form a cultured pearl.
✔✔Pegmatite - ✔✔An igneous rock formed from from cooling, once molten granite that
follows fractures in its surrounding rock. It may contain very large crystals, and its shape
is often thin and contorted.
✔✔Per-carat price - ✔✔The price of a gem divided by its carat weight.
✔✔Phenomenon - ✔✔An unusual optical effect displayed by a gem.
✔✔Pick price - ✔✔A premium price for selecting stones from a parcel.
✔✔Piezoeletricity - ✔✔A property of some crystals that causes them to vibrate at a
constant frequency when subjected to an electrical current.
✔✔Pinpoint - ✔✔Minute inclusion enclosed within a gem; can occur singly or in groups
called clouds.
, ✔✔Placer - ✔✔Workable alluvial deposit of gem material with economic potential.
✔✔Planned light leakage - ✔✔Light that exits through a gem's crown in a controlled
way due to the correct proportions of its cut.
✔✔Plate - ✔✔A section of the earth's rigid outer crust.
✔✔Plate tectonics - ✔✔Study of the formation, structure, and movement of the plates of
the earth's crust.
✔✔Play-of-color - ✔✔The flashing rainbow colors in opal.
✔✔Pleochroism - ✔✔When a gem shows different bodycolors from different crystal
directions.
✔✔Pneumatolysis - ✔✔Crystallization of minerals from a gas.
✔✔Point - ✔✔One one-hundredth of a carat ( 0.01ct. ).
✔✔Polish lines - ✔✔Tiny, parallel grooves on a facet surface left by the polishing
operation.
✔✔Polishing - ✔✔Final stage in gem cutting that produces the smoothest possible
surface.
✔✔Polymer - ✔✔A liquid filling material that's very durable when it dries.
✔✔Potch opal - ✔✔Opal that lacks play-of-color.
✔✔Precious topaz - ✔✔A trade term for orange-to-yellow and brown topaz.
✔✔Preform - ✔✔Rough ground to the approximate shape of the finished stone; also,
the act of producing this shape.
✔✔Primary deposit - ✔✔Gems found in the rock that carried them to the surface.
✔✔Process - ✔✔A procedure that includes cleaning, buffing, and sometimes bleaching,
done to make cultured pearls presentable and appealing.
✔✔Processor - ✔✔A company that prepares cultured pearls for the market.
✔✔Proportions - ✔✔The angles and relative measurements of a polished gem, and the
relationships between them.
QUESTIONS AND ANSWERS SURE A+
✔✔Mantle convection - ✔✔Circulation in the mantle that drives the movement of the
earth's plates.
✔✔Mantle-tissue piece - ✔✔A small square of mantle tissue cut from a donor mollusk
and implanted in a host mollusk with or without a bead.
✔✔Matching tray - ✔✔A grooved, neutrally colored, non-reflective tray, used to match
sets of stones.
✔✔Melt process - ✔✔A synthetic-crystal growth method in which the chemical mixture
is melted, then recrystallized.
✔✔Memo - ✔✔Buying agreement where a dealer entrusts merchandise to a client for
inspection and approval without requiring immediate payment.
✔✔Metamict - ✔✔A mineral that's been broken down from a crystalline to a partly
amorphous state by emanations from radioactive impurities .
✔✔Metamorphic rock - ✔✔Rock altered by heat and pressure, or by heated fluids from
magma.
,✔✔Metric carat - ✔✔The international unit of measurement for gem weight. ( 1 carat
equals 0.20 gram )
✔✔Microcrystalline - ✔✔An aggregate made up of individual crystals visible under
magnification.
✔✔Middle market - ✔✔Market sector where better-quality gemstones are used in well-
finished, moderately priced jewelry pieces.
✔✔Milk and honey - ✔✔a two-toned effect seen when a chatoyant gem is positioned at
right angles to a light source.
✔✔Mine lot (mine run) - ✔✔A mixture of gem qualities that represents unsorted
production from a particular mine.
✔✔Mineral - ✔✔A natural, inorganic substance with a characteristic chemical
composition and usually characteristic structure.
✔✔Mixed cut - ✔✔A cutting style that contains brilliant-cut and step-cut facets.
✔✔Mother-of-pearl - ✔✔The nacreous layer inside a pearl-bearing mollusk's shell.
✔✔Mottling - ✔✔An uneven distribution of color against a contrasting background.
✔✔Mountain jade - ✔✔Thick-skinned jadeite boulders.
✔✔Nacre - ✔✔The natural substance produced by pearl-bearing mollusk's shell.
✔✔Natural gem - ✔✔Gems produced by natural processes, without human help.
✔✔Natural pearl - ✔✔A pearl that forms without human assistance.
✔✔Needle - ✔✔A long, thin inclusion that can be a solid crystal or a hollow tube that
might be filled with a liquid or gas
✔✔Negative crystal - ✔✔An angular, hollow space within a gem that resembles a
mineral inclusion.
✔✔New mine - ✔✔The colored texture category of jadeite.
✔✔Old mine - ✔✔The finest texture category of jadeite.
✔✔Optic axis - ✔✔Direction of single refraction in a doubly refractive gem.
,✔✔Organic - ✔✔Produced by, or derived from, a living organism.
✔✔Orient - ✔✔Iridescence seen in some natural cultured pearls and mother-of-pearl.
✔✔Origin - ✔✔The geographical place where a gem was mined.
✔✔Oxidizing environment - ✔✔An oxygen-rich environment that surrounds a gem
during heat treatment, causing it to absorb oxygen.
✔✔Paraiba tourmaline - ✔✔Trade term for rare, expensive, vibrant green to blue or
violet elbaite tourmaline, originally found only in Brazil's Paraiba state.
✔✔Parcel - ✔✔A quantity of stones, sometimes of similar size and quality, perhaps from
a single mine, but often from various sources, that's offered for sale together.
✔✔Parti-colored - ✔✔Gems that show color zoning with two or more colors.
✔✔Parting - ✔✔A flat break in a gemstone caused by concentrated included minerals
parallel to a twinning plane.
✔✔Pavilion - ✔✔Lower part of a faceted gem below the girdle.
✔✔Pearl - ✔✔A nacreous, organic gem formed in the body of a mollusk.
✔✔Pearl sac - ✔✔Tissue that encloses an implanted bead nucleus and mantle-tissue
piece, or the piece alone, and secretes nacre to form a cultured pearl.
✔✔Pegmatite - ✔✔An igneous rock formed from from cooling, once molten granite that
follows fractures in its surrounding rock. It may contain very large crystals, and its shape
is often thin and contorted.
✔✔Per-carat price - ✔✔The price of a gem divided by its carat weight.
✔✔Phenomenon - ✔✔An unusual optical effect displayed by a gem.
✔✔Pick price - ✔✔A premium price for selecting stones from a parcel.
✔✔Piezoeletricity - ✔✔A property of some crystals that causes them to vibrate at a
constant frequency when subjected to an electrical current.
✔✔Pinpoint - ✔✔Minute inclusion enclosed within a gem; can occur singly or in groups
called clouds.
, ✔✔Placer - ✔✔Workable alluvial deposit of gem material with economic potential.
✔✔Planned light leakage - ✔✔Light that exits through a gem's crown in a controlled
way due to the correct proportions of its cut.
✔✔Plate - ✔✔A section of the earth's rigid outer crust.
✔✔Plate tectonics - ✔✔Study of the formation, structure, and movement of the plates of
the earth's crust.
✔✔Play-of-color - ✔✔The flashing rainbow colors in opal.
✔✔Pleochroism - ✔✔When a gem shows different bodycolors from different crystal
directions.
✔✔Pneumatolysis - ✔✔Crystallization of minerals from a gas.
✔✔Point - ✔✔One one-hundredth of a carat ( 0.01ct. ).
✔✔Polish lines - ✔✔Tiny, parallel grooves on a facet surface left by the polishing
operation.
✔✔Polishing - ✔✔Final stage in gem cutting that produces the smoothest possible
surface.
✔✔Polymer - ✔✔A liquid filling material that's very durable when it dries.
✔✔Potch opal - ✔✔Opal that lacks play-of-color.
✔✔Precious topaz - ✔✔A trade term for orange-to-yellow and brown topaz.
✔✔Preform - ✔✔Rough ground to the approximate shape of the finished stone; also,
the act of producing this shape.
✔✔Primary deposit - ✔✔Gems found in the rock that carried them to the surface.
✔✔Process - ✔✔A procedure that includes cleaning, buffing, and sometimes bleaching,
done to make cultured pearls presentable and appealing.
✔✔Processor - ✔✔A company that prepares cultured pearls for the market.
✔✔Proportions - ✔✔The angles and relative measurements of a polished gem, and the
relationships between them.
