GIA Colored Stone EXAM STUDY GUIDE
2026/2027 ACCURATE QUESTIONS WITH
CORRECT DETAILED SOLUTIONS ||
100% GUARANTEED PASS
<NEWEST VERSION>
1. Mineral - ANSWER ✔ A natural, inorganic substance with a characteristic
chemical composition and usually characteristic structure.
2. Mixed cut - ANSWER ✔ A cutting style that combines brilliant-cut and
step cut facets.
3. Abrasions - ANSWER ✔ Tiny nicks and pits caused by wear and damage
to a gem's facet edges or culet.
4. Absorption spectrum - ANSWER ✔ A pattern of dark vertical lines or
bands shown by certain gems when viewed through a spectroscope.
5. Adularescence - ANSWER ✔ The cloudy bluish white light in a
moonstone, caused by scattering of light.
6. Agate - ANSWER ✔ Chalcedony with a curved or angular bands or layers
that differ in color and transparency .
7. Aggregate - ANSWER ✔ A mass of tiny, randomly oriented crystals.
8. Akoya - ANSWER ✔ Common name for the Pinctada fucata oyster and
the natural or cultured pearls it produces.
9. Allochromatic - ANSWER ✔ A gem colored by trace elements in its
crystal structure.
,10.Alluvial deposit - ANSWER ✔ A deposit where gems are eroded from
their source rock, then transported away from their source and further
concentrated.
11.Amorphous - ANSWER ✔ Lacking a regular crystal structure.
12.Aragonite - ANSWER ✔ A crystalized form of calcium carbonate found in
nacre.
13.Assembled stone - ANSWER ✔ Two or more separate pieces of material
joined to form a unit.
14.Asterism - ANSWER ✔ Crossing of chatoyant bands, creating a star in the
dome of cabochon.
15.Atom - ANSWER ✔ The basic structural unit of all matter.
16.What is the transparency of gray-base black opal ? - ANSWER ✔
Translucent to opaque
17.The type of matrix found as a layer in finished boulder opal is - ANSWER
✔ Ironstone.
18.Experts think fire opal's background color is caused by - ANSWER ✔ iron
impurities.
19.In opal, a pattern of large, distinct, usually rectangular patches of play-of-
color with edges that touch each is called - ANSWER ✔ harlequin.
20.Play-of-color that's seen only when light travels through an opal to the eye
called - ANSWER ✔ contra luz.
21.The first black opals were discovered in - ANSWER ✔ New South Wales.
22.What is the first step in evaluating an opal ? - ANSWER ✔ Determine its
type
,23.Which treatment involves immersing opal in concentrated sulfuric acid ? -
ANSWER ✔ Sugar
24.Who created the first marketable synthetic opal ? - ANSWER ✔ Pierre
Gilson
25.Plastic imitation opal was first marketed in the late 1980s in - ANSWER ✔
Japan.
26.Cryptocrystalline quartz is known as - ANSWER ✔ chalcedony.
27.Chalcedony with curved or angular bands or layers that differ in color and
transparency is known as - ANSWER ✔ agate.
28.Which of the following has the smallest crystal size ? - ANSWER ✔
Cryptocrystalline aggregates
29.In the nineteenth century, a major source of amethyst was discovered in -
ANSWER ✔ Brazil.
30.The color of amethyst results from - ANSWER ✔ color centers acting on
iron.
31.One of amethyst's finest colors is - ANSWER ✔ medium-dark strong
reddish purple.
32.The major commercial-quality amethyst source is - ANSWER ✔ Brazil.
33."Maraba" amethyst is often - ANSWER ✔ uniform in color.
34.You should judge a gemstone's beauty and value only by comparing it with
others of its own ___________ or ___________. - ANSWER ✔ species or
variety
35._____________ ____________with fine color are more common in some
colored stone species than in others. - ANSWER ✔ large stones
, 36.In many gemstone varieties, _________ _____ are more valued than mixed
hues. - ANSWER ✔ pure hues
37.You __________________ use trade terms that imply a gem's geographic
origin if you can't be sure of its actual source. - ANSWER ✔ shouldn't
38.The way a gem is cut can have a dramatic effect on its ___________-___
_________. - ANSWER ✔ face-up color
39.The cutter's main goal is to produce a stone with the highest possible
__________. - ANSWER ✔ value
40.If rough is very valuable, cutters often compromise on ______________ to
save weight and avoid loss of money. - ANSWER ✔ proportions
41.Cutting compromises that save weight can also cause _____________ and/or
_____________. - ANSWER ✔ extinction windowing
42.When you can't control the lighting conditions in a buying situation, use
your own _____________ ___________ or ___________ _____________. -
ANSWER ✔ comparison stones color samples
43.______________ _____________ are very important when grading colored
stones. - ANSWER ✔ consistent procedures
44.Know a gem's _____________ before you grade it. - ANSWER ✔ identity
45.In general, attractive colored stones tend to have highly saturated _______
and medium to medium-dark _______. - ANSWER ✔ hues tone
46.Hues with very light or very dark tone usually don't reach the same high
levels of saturation as those with _____________ tone. - ANSWER ✔
medium
47.Larger stones can appear more saturated than smaller stones cut from the
same ____________. - ANSWER ✔ rough
2026/2027 ACCURATE QUESTIONS WITH
CORRECT DETAILED SOLUTIONS ||
100% GUARANTEED PASS
<NEWEST VERSION>
1. Mineral - ANSWER ✔ A natural, inorganic substance with a characteristic
chemical composition and usually characteristic structure.
2. Mixed cut - ANSWER ✔ A cutting style that combines brilliant-cut and
step cut facets.
3. Abrasions - ANSWER ✔ Tiny nicks and pits caused by wear and damage
to a gem's facet edges or culet.
4. Absorption spectrum - ANSWER ✔ A pattern of dark vertical lines or
bands shown by certain gems when viewed through a spectroscope.
5. Adularescence - ANSWER ✔ The cloudy bluish white light in a
moonstone, caused by scattering of light.
6. Agate - ANSWER ✔ Chalcedony with a curved or angular bands or layers
that differ in color and transparency .
7. Aggregate - ANSWER ✔ A mass of tiny, randomly oriented crystals.
8. Akoya - ANSWER ✔ Common name for the Pinctada fucata oyster and
the natural or cultured pearls it produces.
9. Allochromatic - ANSWER ✔ A gem colored by trace elements in its
crystal structure.
,10.Alluvial deposit - ANSWER ✔ A deposit where gems are eroded from
their source rock, then transported away from their source and further
concentrated.
11.Amorphous - ANSWER ✔ Lacking a regular crystal structure.
12.Aragonite - ANSWER ✔ A crystalized form of calcium carbonate found in
nacre.
13.Assembled stone - ANSWER ✔ Two or more separate pieces of material
joined to form a unit.
14.Asterism - ANSWER ✔ Crossing of chatoyant bands, creating a star in the
dome of cabochon.
15.Atom - ANSWER ✔ The basic structural unit of all matter.
16.What is the transparency of gray-base black opal ? - ANSWER ✔
Translucent to opaque
17.The type of matrix found as a layer in finished boulder opal is - ANSWER
✔ Ironstone.
18.Experts think fire opal's background color is caused by - ANSWER ✔ iron
impurities.
19.In opal, a pattern of large, distinct, usually rectangular patches of play-of-
color with edges that touch each is called - ANSWER ✔ harlequin.
20.Play-of-color that's seen only when light travels through an opal to the eye
called - ANSWER ✔ contra luz.
21.The first black opals were discovered in - ANSWER ✔ New South Wales.
22.What is the first step in evaluating an opal ? - ANSWER ✔ Determine its
type
,23.Which treatment involves immersing opal in concentrated sulfuric acid ? -
ANSWER ✔ Sugar
24.Who created the first marketable synthetic opal ? - ANSWER ✔ Pierre
Gilson
25.Plastic imitation opal was first marketed in the late 1980s in - ANSWER ✔
Japan.
26.Cryptocrystalline quartz is known as - ANSWER ✔ chalcedony.
27.Chalcedony with curved or angular bands or layers that differ in color and
transparency is known as - ANSWER ✔ agate.
28.Which of the following has the smallest crystal size ? - ANSWER ✔
Cryptocrystalline aggregates
29.In the nineteenth century, a major source of amethyst was discovered in -
ANSWER ✔ Brazil.
30.The color of amethyst results from - ANSWER ✔ color centers acting on
iron.
31.One of amethyst's finest colors is - ANSWER ✔ medium-dark strong
reddish purple.
32.The major commercial-quality amethyst source is - ANSWER ✔ Brazil.
33."Maraba" amethyst is often - ANSWER ✔ uniform in color.
34.You should judge a gemstone's beauty and value only by comparing it with
others of its own ___________ or ___________. - ANSWER ✔ species or
variety
35._____________ ____________with fine color are more common in some
colored stone species than in others. - ANSWER ✔ large stones
, 36.In many gemstone varieties, _________ _____ are more valued than mixed
hues. - ANSWER ✔ pure hues
37.You __________________ use trade terms that imply a gem's geographic
origin if you can't be sure of its actual source. - ANSWER ✔ shouldn't
38.The way a gem is cut can have a dramatic effect on its ___________-___
_________. - ANSWER ✔ face-up color
39.The cutter's main goal is to produce a stone with the highest possible
__________. - ANSWER ✔ value
40.If rough is very valuable, cutters often compromise on ______________ to
save weight and avoid loss of money. - ANSWER ✔ proportions
41.Cutting compromises that save weight can also cause _____________ and/or
_____________. - ANSWER ✔ extinction windowing
42.When you can't control the lighting conditions in a buying situation, use
your own _____________ ___________ or ___________ _____________. -
ANSWER ✔ comparison stones color samples
43.______________ _____________ are very important when grading colored
stones. - ANSWER ✔ consistent procedures
44.Know a gem's _____________ before you grade it. - ANSWER ✔ identity
45.In general, attractive colored stones tend to have highly saturated _______
and medium to medium-dark _______. - ANSWER ✔ hues tone
46.Hues with very light or very dark tone usually don't reach the same high
levels of saturation as those with _____________ tone. - ANSWER ✔
medium
47.Larger stones can appear more saturated than smaller stones cut from the
same ____________. - ANSWER ✔ rough
