GIA COLORED STONES 680 QUESTIONS & CORRECT
ANSWERS LATEST 2025
A natural, inorganic substance with a characteristic chemical composition and
usually characteristic structure. - ANSWER-Mineral
A cutting style that combines brilliant-cut and step cut facets. - ANSWER-Mixed
cut
Tiny nicks and pits caused by wear and damage to a gem's facet edges or culet. -
ANSWER-Abrasions
A pattern of dark vertical lines or bands shown by certain gems when viewed
through a spectroscope. - ANSWER-Absorption spectrum
The cloudy bluish white light in a moonstone, caused by scattering of light. -
ANSWER-Adularescence
Chalcedony with a curved or angular bands or layers that differ in color and
transparency . - ANSWER-Agate
A mass of tiny, randomly oriented crystals. - ANSWER-Aggregate
Common name for the Pinctada fucata oyster and the natural or cultured pearls it
produces. - ANSWER-Akoya
,A gem colored by trace elements in its crystal structure. - ANSWER-
Allochromatic
A deposit where gems are eroded from their source rock, then transported away
from their source and further concentrated. - ANSWER-Alluvial deposit
Lacking a regular crystal structure. - ANSWER-Amorphous
A crystalized form of calcium carbonate found in nacre. - ANSWER-Aragonite
Two or more separate pieces of material joined to form a unit. - ANSWER-
Assembled stone
Crossing of chatoyant bands, creating a star in the dome of cabochon. - ANSWER-
Asterism
The basic structural unit of all matter. - ANSWER-Atom
A glittery effect caused by light reflecting from small, flat inclusions within a
gemstone. - ANSWER-Aventurescence
An opal's bodycolor, independent of its play-of-color. - ANSWER-Background
color
A bead used as the core of a cultured pearl, usually made from a freshwater mussel
shell. - ANSWER-Bead nucleus
A treatment that uses chemicals to lighten or remove color. - ANSWER-Bleaching
,Characteristic or irregularity confined to the surface of a polished gemstone. -
ANSWER-Blemish
Trade term for a highly prized, vivid blue adularescence displayed by the finest
moonstone. - ANSWER-Blue Sheen
A gemstone's basic color, determined by its selective absorption of light. -
ANSWER-Bodycolor
A crystal growth habit with a bumpy appearance similar to a bunch of grapes. -
ANSWER-Botryoidal
Thin layers of precious opal, cut to include matrix. - ANSWER-Boulder opal
A cylindrical synthetic crystal produced by the flame-fusion process. - ANSWER-
Boule
Light that eventually returns to the eye after entering a gem through the crown,
reflecting off its pavilion facets, and exiting back through the crown. - ANSWER-
Brilliance
Cutting style with triangular or kite-shaped facets that radiate from the center
toward girdle. - ANSWER-Brilliant cut
A smoothly rounded polished gem with a domed top and a flat or curved base. -
ANSWER-Cabochon
, A non-nacreous natural "pearl". - ANSWER-Calcareous concretion
Gemstone sizes cut to fit standard mountings. - ANSWER-Calibrated sizes
A gem carving style in which the design often a women's profile, projects slightly
from a flat or curved surface. - ANSWER-Cameo
An opening that extends into a gem from the surface. - ANSWER-Cavity
Tiny tension cracks in a moonstone that interfere with adularescence and reduce
value. - ANSWER-Centipedes
A process in which ground powder is heated, sometimes under pressure, to
produce a fine-grained solid material. - ANSWER-Ceramic process
A document that indicates a stone's geographic origin, based on its inclusions and
trace element chemistry. - ANSWER-Certificate of origin
A cryptocrystalline quartz aggregate. - ANSWER-Chalcedony
A process where the electrons that selectively absorb light are passed back and
forth between neighboring impurity ions. - ANSWER-Charge transfer
Bands of light in certain gems, caused by reflection of light from many parallel,
needle-like inclusions or hollow tubes. - ANSWER-Chatoyancy
Kinds and relative quantities of atoms that make up a material. - ANSWER-
Chemical composition
ANSWERS LATEST 2025
A natural, inorganic substance with a characteristic chemical composition and
usually characteristic structure. - ANSWER-Mineral
A cutting style that combines brilliant-cut and step cut facets. - ANSWER-Mixed
cut
Tiny nicks and pits caused by wear and damage to a gem's facet edges or culet. -
ANSWER-Abrasions
A pattern of dark vertical lines or bands shown by certain gems when viewed
through a spectroscope. - ANSWER-Absorption spectrum
The cloudy bluish white light in a moonstone, caused by scattering of light. -
ANSWER-Adularescence
Chalcedony with a curved or angular bands or layers that differ in color and
transparency . - ANSWER-Agate
A mass of tiny, randomly oriented crystals. - ANSWER-Aggregate
Common name for the Pinctada fucata oyster and the natural or cultured pearls it
produces. - ANSWER-Akoya
,A gem colored by trace elements in its crystal structure. - ANSWER-
Allochromatic
A deposit where gems are eroded from their source rock, then transported away
from their source and further concentrated. - ANSWER-Alluvial deposit
Lacking a regular crystal structure. - ANSWER-Amorphous
A crystalized form of calcium carbonate found in nacre. - ANSWER-Aragonite
Two or more separate pieces of material joined to form a unit. - ANSWER-
Assembled stone
Crossing of chatoyant bands, creating a star in the dome of cabochon. - ANSWER-
Asterism
The basic structural unit of all matter. - ANSWER-Atom
A glittery effect caused by light reflecting from small, flat inclusions within a
gemstone. - ANSWER-Aventurescence
An opal's bodycolor, independent of its play-of-color. - ANSWER-Background
color
A bead used as the core of a cultured pearl, usually made from a freshwater mussel
shell. - ANSWER-Bead nucleus
A treatment that uses chemicals to lighten or remove color. - ANSWER-Bleaching
,Characteristic or irregularity confined to the surface of a polished gemstone. -
ANSWER-Blemish
Trade term for a highly prized, vivid blue adularescence displayed by the finest
moonstone. - ANSWER-Blue Sheen
A gemstone's basic color, determined by its selective absorption of light. -
ANSWER-Bodycolor
A crystal growth habit with a bumpy appearance similar to a bunch of grapes. -
ANSWER-Botryoidal
Thin layers of precious opal, cut to include matrix. - ANSWER-Boulder opal
A cylindrical synthetic crystal produced by the flame-fusion process. - ANSWER-
Boule
Light that eventually returns to the eye after entering a gem through the crown,
reflecting off its pavilion facets, and exiting back through the crown. - ANSWER-
Brilliance
Cutting style with triangular or kite-shaped facets that radiate from the center
toward girdle. - ANSWER-Brilliant cut
A smoothly rounded polished gem with a domed top and a flat or curved base. -
ANSWER-Cabochon
, A non-nacreous natural "pearl". - ANSWER-Calcareous concretion
Gemstone sizes cut to fit standard mountings. - ANSWER-Calibrated sizes
A gem carving style in which the design often a women's profile, projects slightly
from a flat or curved surface. - ANSWER-Cameo
An opening that extends into a gem from the surface. - ANSWER-Cavity
Tiny tension cracks in a moonstone that interfere with adularescence and reduce
value. - ANSWER-Centipedes
A process in which ground powder is heated, sometimes under pressure, to
produce a fine-grained solid material. - ANSWER-Ceramic process
A document that indicates a stone's geographic origin, based on its inclusions and
trace element chemistry. - ANSWER-Certificate of origin
A cryptocrystalline quartz aggregate. - ANSWER-Chalcedony
A process where the electrons that selectively absorb light are passed back and
forth between neighboring impurity ions. - ANSWER-Charge transfer
Bands of light in certain gems, caused by reflection of light from many parallel,
needle-like inclusions or hollow tubes. - ANSWER-Chatoyancy
Kinds and relative quantities of atoms that make up a material. - ANSWER-
Chemical composition
