GIA COLORED STONE UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
COMPREHENSIVE STUDY GUIDE
●● 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
QUESTIONS AND CORRECT ANSWERS
COMPREHENSIVE STUDY GUIDE
●● 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
