GIA Colored Stones Final Review Exam
Questions And 100% Correct Answers
2025-2026 Updated.
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.
,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.
,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.
, 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.
Color zoning - Answer Areas of different color in a gem, caused by variations in growth
conditions.
Colorless impregnation - Answer Filling of pores or other openings with melted wax, resin,
polymer, or plastic to improve appearance and stability.
Commercial market - Answer Market sector where average-quality gemstones are used in
mass-market jewelry.
Conchiolin - Answer The organic "glue" in nacre that holds aragonite platelets together.
Conchoidal fracture - Answer A curved and ridged fracture in a gemstone, extending from the
surface inward.
Consignment - Answer A selection of goods loaned to a dealer by another wholesaler or gem
cutter.
Questions And 100% Correct Answers
2025-2026 Updated.
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.
,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.
,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.
, 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.
Color zoning - Answer Areas of different color in a gem, caused by variations in growth
conditions.
Colorless impregnation - Answer Filling of pores or other openings with melted wax, resin,
polymer, or plastic to improve appearance and stability.
Commercial market - Answer Market sector where average-quality gemstones are used in
mass-market jewelry.
Conchiolin - Answer The organic "glue" in nacre that holds aragonite platelets together.
Conchoidal fracture - Answer A curved and ridged fracture in a gemstone, extending from the
surface inward.
Consignment - Answer A selection of goods loaned to a dealer by another wholesaler or gem
cutter.
