GIA Colored StoneS fInAl exAm QueStIonS And AnSwerS
PrACtICe QueStIonS wIth SolutIonS neweSt 2026 /2027 |
AlreAdy GrAded A+
Mineral - AnSwer-A natural, inorganic substance with a characteristic chemical
composition and usually characteristic structure.
Mixed cut - AnSwer-A cutting style that combines brilliant-cut and step cut facets.
Abrasions - AnSwer-Tiny nicks and pits caused by wear and damage to a gem's facet
edges or culet.
Absorption spectrum - AnSwer-A pattern of dark vertical lines or bands shown by certain
gems when viewed through a spectroscope.
Adularescence - AnSwer-The cloudy bluish white light in a moonstone, caused by
scattering of light.
Agate - AnSwer-Chalcedony with a curved or angular bands or layers that differ in color
and transparency .
Aggregate - AnSwer-A mass of tiny, randomly oriented crystals.
Akoya - AnSwer-Common name for the Pinctada fucata oyster and the natural or
cultured pearls it produces.
Allochromatic - AnSwer-A gem colored by trace elements in its crystal structure.
Alluvial deposit - AnSwer-A deposit where gems are eroded from their source rock, then
transported away from their source and further concentrated.
,Amorphous - AnSwer-Lacking a regular crystal structure.
Aragonite - AnSwer-A crystalized form of calcium carbonate found in nacre.
Assembled stone - AnSwer-Two or more separate pieces of material joined to form a
unit.
Asterism - AnSwer-Crossing of chatoyant bands, creating a star in the dome of
cabochon.
Atom - AnSwer-The basic structural unit of all matter.
Aventurescence - AnSwer-A glittery effect caused by light reflecting from small, flat
inclusions within a gemstone.
Background color - AnSwer-An opal's bodycolor, independent of its play-of-color.
Bead nucleus - AnSwer-A bead used as the core of a cultured pearl, usually made from a
freshwater mussel shell.
Bleaching - AnSwer-A treatment that uses chemicals to lighten or remove color.
Blemish - AnSwer-Characteristic or irregularity confined to the surface of a polished
gemstone.
Blue Sheen - AnSwer-Trade term for a highly prized, vivid blue adularescence displayed
by the finest moonstone.
Bodycolor - AnSwer-A gemstone's basic color, determined by its selective absorption of
light.
,Botryoidal - AnSwer-A crystal growth habit with a bumpy appearance similar to a bunch
of grapes.
Boulder opal - AnSwer-Thin layers of precious opal, cut to include matrix.
Boule - AnSwer-A cylindrical synthetic crystal produced by the flame-fusion process.
Brilliance - AnSwer-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.
Brilliant cut - AnSwer-Cutting style with triangular or kite-shaped facets that radiate from
the center toward girdle.
Cabochon - AnSwer-A smoothly rounded polished gem with a domed top and a flat or
curved base.
Calcareous concretion - AnSwer-A non-nacreous natural "pearl".
Calibrated sizes - AnSwer-Gemstone sizes cut to fit standard mountings.
Cameo - AnSwer-A gem carving style in which the design often a women's profile,
projects slightly from a flat or curved surface.
Cavity - AnSwer-An opening that extends into a gem from the surface.
Centipedes - AnSwer-Tiny tension cracks in a moonstone that interfere with
adularescence and reduce value.
Ceramic process - AnSwer-A process in which ground powder is heated, sometimes
under pressure, to produce a fine-grained solid material.
, Certificate of origin - AnSwer-A document that indicates a stone's geographic origin,
based on its inclusions and trace element chemistry.
Chalcedony - AnSwer-A cryptocrystalline quartz aggregate.
Charge transfer - AnSwer-A process where the electrons that selectively absorb light are
passed back and forth between neighboring impurity ions.
Chatoyancy - AnSwer-Bands of light in certain gems, caused by reflection of light from
many parallel, needle-like inclusions or hollow tubes.
Chemical composition - AnSwer-Kinds and relative quantities of atoms that make up a
material.
Chemical element - AnSwer-A substance that consists of atoms of only one kind.
Chip - AnSwer-A damaged area on a gem, usually near the girdle.
Chrome tourmaline - AnSwer-Trade term for a vibrant green tourmaline that's colored by
traces of vanadium, chromium, or both.
Circled pearl - AnSwer-A pearl with one or more grooved or ridged rings all the way
around it.
Cleavage - AnSwer-A smooth, flat break in a gemstone parallel to planes of atomic
weakness, caused by weak or fewer bonds between atoms or both.
Cloud - AnSwer-Any hazy or milky area that cannot be described as a feather, fingerprint,
or group of included crystals or needles.
PrACtICe QueStIonS wIth SolutIonS neweSt 2026 /2027 |
AlreAdy GrAded A+
Mineral - AnSwer-A natural, inorganic substance with a characteristic chemical
composition and usually characteristic structure.
Mixed cut - AnSwer-A cutting style that combines brilliant-cut and step cut facets.
Abrasions - AnSwer-Tiny nicks and pits caused by wear and damage to a gem's facet
edges or culet.
Absorption spectrum - AnSwer-A pattern of dark vertical lines or bands shown by certain
gems when viewed through a spectroscope.
Adularescence - AnSwer-The cloudy bluish white light in a moonstone, caused by
scattering of light.
Agate - AnSwer-Chalcedony with a curved or angular bands or layers that differ in color
and transparency .
Aggregate - AnSwer-A mass of tiny, randomly oriented crystals.
Akoya - AnSwer-Common name for the Pinctada fucata oyster and the natural or
cultured pearls it produces.
Allochromatic - AnSwer-A gem colored by trace elements in its crystal structure.
Alluvial deposit - AnSwer-A deposit where gems are eroded from their source rock, then
transported away from their source and further concentrated.
,Amorphous - AnSwer-Lacking a regular crystal structure.
Aragonite - AnSwer-A crystalized form of calcium carbonate found in nacre.
Assembled stone - AnSwer-Two or more separate pieces of material joined to form a
unit.
Asterism - AnSwer-Crossing of chatoyant bands, creating a star in the dome of
cabochon.
Atom - AnSwer-The basic structural unit of all matter.
Aventurescence - AnSwer-A glittery effect caused by light reflecting from small, flat
inclusions within a gemstone.
Background color - AnSwer-An opal's bodycolor, independent of its play-of-color.
Bead nucleus - AnSwer-A bead used as the core of a cultured pearl, usually made from a
freshwater mussel shell.
Bleaching - AnSwer-A treatment that uses chemicals to lighten or remove color.
Blemish - AnSwer-Characteristic or irregularity confined to the surface of a polished
gemstone.
Blue Sheen - AnSwer-Trade term for a highly prized, vivid blue adularescence displayed
by the finest moonstone.
Bodycolor - AnSwer-A gemstone's basic color, determined by its selective absorption of
light.
,Botryoidal - AnSwer-A crystal growth habit with a bumpy appearance similar to a bunch
of grapes.
Boulder opal - AnSwer-Thin layers of precious opal, cut to include matrix.
Boule - AnSwer-A cylindrical synthetic crystal produced by the flame-fusion process.
Brilliance - AnSwer-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.
Brilliant cut - AnSwer-Cutting style with triangular or kite-shaped facets that radiate from
the center toward girdle.
Cabochon - AnSwer-A smoothly rounded polished gem with a domed top and a flat or
curved base.
Calcareous concretion - AnSwer-A non-nacreous natural "pearl".
Calibrated sizes - AnSwer-Gemstone sizes cut to fit standard mountings.
Cameo - AnSwer-A gem carving style in which the design often a women's profile,
projects slightly from a flat or curved surface.
Cavity - AnSwer-An opening that extends into a gem from the surface.
Centipedes - AnSwer-Tiny tension cracks in a moonstone that interfere with
adularescence and reduce value.
Ceramic process - AnSwer-A process in which ground powder is heated, sometimes
under pressure, to produce a fine-grained solid material.
, Certificate of origin - AnSwer-A document that indicates a stone's geographic origin,
based on its inclusions and trace element chemistry.
Chalcedony - AnSwer-A cryptocrystalline quartz aggregate.
Charge transfer - AnSwer-A process where the electrons that selectively absorb light are
passed back and forth between neighboring impurity ions.
Chatoyancy - AnSwer-Bands of light in certain gems, caused by reflection of light from
many parallel, needle-like inclusions or hollow tubes.
Chemical composition - AnSwer-Kinds and relative quantities of atoms that make up a
material.
Chemical element - AnSwer-A substance that consists of atoms of only one kind.
Chip - AnSwer-A damaged area on a gem, usually near the girdle.
Chrome tourmaline - AnSwer-Trade term for a vibrant green tourmaline that's colored by
traces of vanadium, chromium, or both.
Circled pearl - AnSwer-A pearl with one or more grooved or ridged rings all the way
around it.
Cleavage - AnSwer-A smooth, flat break in a gemstone parallel to planes of atomic
weakness, caused by weak or fewer bonds between atoms or both.
Cloud - AnSwer-Any hazy or milky area that cannot be described as a feather, fingerprint,
or group of included crystals or needles.
