GIA COLORED STONES QUIZZES
WITH VERIFIED ANSWERS.
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.
Cobbing ANSWER : -Removing heavily included sections from a gemstone rough by carefully tapping it
with a small hammer.
Color center ANSWER : -A small defect in the atomic structure of a material that absorb light and give
rise to a color.
Color Change ANSWER : -A distinct change in gem color under different types of lighting.
Color range ANSWER : -The selection of colors in which a gemstone occurs.
WITH VERIFIED ANSWERS.
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.
Cobbing ANSWER : -Removing heavily included sections from a gemstone rough by carefully tapping it
with a small hammer.
Color center ANSWER : -A small defect in the atomic structure of a material that absorb light and give
rise to a color.
Color Change ANSWER : -A distinct change in gem color under different types of lighting.
Color range ANSWER : -The selection of colors in which a gemstone occurs.
