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GIA Colored Stones Exam 2025–2026
Gemology, Pearls & Colored Stones
Certification Study Guide & Exam Review
An intense, unstable green color can be created in spodumene by - CORRECT
ANSWER=irradiation
The adularescence of the finest moonstones is - CORRECT ANSWER=blue
mantle - CORRECT ANSWER=The organ that lines the mollusk's shell, enclosed its soft body
and contains the cells that form pearl sacs and secrete nacre.
Hatchery Bred - CORRECT ANSWER=Describes mollusks bred in lab tanks and grown in
protected areas rather than collected as adults in the wild.
Value Factors - CORRECT ANSWER=Features used to judge the quality and value of pearls.
Cultured Pearl - CORRECT ANSWER=A pearl formed as the result of human intervention in
the formation process.
Uniform Strand - CORRECT ANSWER=A necklace featuring pearls that are very nearly the
same size.
Aragonite - CORRECT ANSWER=A crystallized form of calcium carbonate found in nacre.
Processor - CORRECT ANSWER=A company that prepares cultured pearls for the market.
Conchilolin - CORRECT ANSWER=The organic "glue" in nacre that holds aragonite platelets
together.
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Calcareous Concretion - CORRECT ANSWER=A non-nacreous natural "pearl."
Surface Chacteristics - CORRECT ANSWER=Blemishes or irregularities confined to a pearls
surface.
Cultured Blister Pearl - CORRECT ANSWER=A cultured pearl grown around a nucleus glued
under the mantle tissue inside a mollusk's shell.
Pearl Sac - CORRECT ANSWER=Tissue that encloses an implanted bead necleus and mantle
tissue piece, forms a cultured pearl.
Mabe - CORRECT ANSWER=An assembly composed of a nacre dome, filler, & mother of
pearl backing.
Mantle Tissue Piece - CORRECT ANSWER=A small square of mantle tissue cut from a donor
mollusk and implanted in a host mollusk with or without a bead.
By which era has moonstone gone out of style - CORRECT ANSWER=art deco
The color of chrome diopside is - CORRECT ANSWER=natural
Tiny tension cracks in moonstone are called - CORRECT ANSWER=centipedes
Kunzite's most common color is - CORRECT ANSWER=light pink
Yellow spodumene is called - CORRECT ANSWER=triphane
The greenish blue feldspar that has grid-like white streaks and resembles turquoise is -
CORRECT ANSWER=amazonite
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The best-known feldspar species that includes moonstone is - CORRECT ANSWER=orthoclase
Which of the following is the only known commercial source of chrome diopside - CORRECT
ANSWER=russia
How many cleavage directions are found in feldspar, spodumene, and diopside - CORRECT
ANSWER=two
Spectrolite is a variety of - CORRECT ANSWER=Labradorite
Coral's most valuable color is - CORRECT ANSWER=red
Which amber color is most valuable - CORRECT ANSWER=red
Which of the following gems is a natural glass - CORRECT ANSWER=Moldavite
Mineral - CORRECT ANSWER=A natural, inorganic substance with a characteristic chemical
composition and usually characteristic structure.
Mixed cut - CORRECT ANSWER=A cutting style that combines brilliant-cut and step cut
facets.
Abrasions - CORRECT ANSWER=Tiny nicks and pits caused by wear and damage to a gem's
facet edges or culet.
Absorption spectrum - CORRECT ANSWER=A pattern of dark vertical lines or bands shown
by certain gems when viewed through a spectroscope.
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Adularescence - CORRECT ANSWER=The cloudy bluish white light in a moonstone, caused
by scattering of light.
Agate - CORRECT ANSWER=Chalcedony with a curved or angular bands or layers that differ
in color and transparency .
Aggregate - CORRECT ANSWER=A mass of tiny, randomly oriented crystals.
Akoya - CORRECT ANSWER=Common name for the Pinctada fucata oyster and the natural or
cultured pearls it produces.
Allochromatic - CORRECT ANSWER=A gem colored by trace elements in its crystal structure.
Alluvial deposit - CORRECT ANSWER=A deposit where gems are eroded from their source
rock, then transported away from their source and further concentrated.
Amorphous - CORRECT ANSWER=Lacking a regular crystal structure.
Aragonite - CORRECT ANSWER=A crystalized form of calcium carbonate found in nacre.
Assembled stone - CORRECT ANSWER=Two or more separate pieces of material joined to
form a unit.
Asterism - CORRECT ANSWER=Crossing of chatoyant bands, creating a star in the dome of
cabochon.
Atom - CORRECT ANSWER=The basic structural unit of all matter.
GIA Colored Stones Exam 2025–2026
Gemology, Pearls & Colored Stones
Certification Study Guide & Exam Review
An intense, unstable green color can be created in spodumene by - CORRECT
ANSWER=irradiation
The adularescence of the finest moonstones is - CORRECT ANSWER=blue
mantle - CORRECT ANSWER=The organ that lines the mollusk's shell, enclosed its soft body
and contains the cells that form pearl sacs and secrete nacre.
Hatchery Bred - CORRECT ANSWER=Describes mollusks bred in lab tanks and grown in
protected areas rather than collected as adults in the wild.
Value Factors - CORRECT ANSWER=Features used to judge the quality and value of pearls.
Cultured Pearl - CORRECT ANSWER=A pearl formed as the result of human intervention in
the formation process.
Uniform Strand - CORRECT ANSWER=A necklace featuring pearls that are very nearly the
same size.
Aragonite - CORRECT ANSWER=A crystallized form of calcium carbonate found in nacre.
Processor - CORRECT ANSWER=A company that prepares cultured pearls for the market.
Conchilolin - CORRECT ANSWER=The organic "glue" in nacre that holds aragonite platelets
together.
,2|Page
Calcareous Concretion - CORRECT ANSWER=A non-nacreous natural "pearl."
Surface Chacteristics - CORRECT ANSWER=Blemishes or irregularities confined to a pearls
surface.
Cultured Blister Pearl - CORRECT ANSWER=A cultured pearl grown around a nucleus glued
under the mantle tissue inside a mollusk's shell.
Pearl Sac - CORRECT ANSWER=Tissue that encloses an implanted bead necleus and mantle
tissue piece, forms a cultured pearl.
Mabe - CORRECT ANSWER=An assembly composed of a nacre dome, filler, & mother of
pearl backing.
Mantle Tissue Piece - CORRECT ANSWER=A small square of mantle tissue cut from a donor
mollusk and implanted in a host mollusk with or without a bead.
By which era has moonstone gone out of style - CORRECT ANSWER=art deco
The color of chrome diopside is - CORRECT ANSWER=natural
Tiny tension cracks in moonstone are called - CORRECT ANSWER=centipedes
Kunzite's most common color is - CORRECT ANSWER=light pink
Yellow spodumene is called - CORRECT ANSWER=triphane
The greenish blue feldspar that has grid-like white streaks and resembles turquoise is -
CORRECT ANSWER=amazonite
,3|Page
The best-known feldspar species that includes moonstone is - CORRECT ANSWER=orthoclase
Which of the following is the only known commercial source of chrome diopside - CORRECT
ANSWER=russia
How many cleavage directions are found in feldspar, spodumene, and diopside - CORRECT
ANSWER=two
Spectrolite is a variety of - CORRECT ANSWER=Labradorite
Coral's most valuable color is - CORRECT ANSWER=red
Which amber color is most valuable - CORRECT ANSWER=red
Which of the following gems is a natural glass - CORRECT ANSWER=Moldavite
Mineral - CORRECT ANSWER=A natural, inorganic substance with a characteristic chemical
composition and usually characteristic structure.
Mixed cut - CORRECT ANSWER=A cutting style that combines brilliant-cut and step cut
facets.
Abrasions - CORRECT ANSWER=Tiny nicks and pits caused by wear and damage to a gem's
facet edges or culet.
Absorption spectrum - CORRECT ANSWER=A pattern of dark vertical lines or bands shown
by certain gems when viewed through a spectroscope.
, 4|Page
Adularescence - CORRECT ANSWER=The cloudy bluish white light in a moonstone, caused
by scattering of light.
Agate - CORRECT ANSWER=Chalcedony with a curved or angular bands or layers that differ
in color and transparency .
Aggregate - CORRECT ANSWER=A mass of tiny, randomly oriented crystals.
Akoya - CORRECT ANSWER=Common name for the Pinctada fucata oyster and the natural or
cultured pearls it produces.
Allochromatic - CORRECT ANSWER=A gem colored by trace elements in its crystal structure.
Alluvial deposit - CORRECT ANSWER=A deposit where gems are eroded from their source
rock, then transported away from their source and further concentrated.
Amorphous - CORRECT ANSWER=Lacking a regular crystal structure.
Aragonite - CORRECT ANSWER=A crystalized form of calcium carbonate found in nacre.
Assembled stone - CORRECT ANSWER=Two or more separate pieces of material joined to
form a unit.
Asterism - CORRECT ANSWER=Crossing of chatoyant bands, creating a star in the dome of
cabochon.
Atom - CORRECT ANSWER=The basic structural unit of all matter.
