GEM 220 QUIZ Flashcards
A gem produced by, or derived from, a living organism is A. organic. B. synthetic. C. inorganic. D. manmade.
Organic.
Which of the following is an organic gem? A. Jade B. Ruby C. Amber D. Tourmaline
Amber
A substance that consists of atoms of only one kind is a A. mineral. B. unit cell. C. gem species. D. chemical element.
Chemical element.
A natural, inorganic substance with a characteristic chemical composition and usually characteristic crystal structure is a(n) A. atom. B. mineral. C. synthetic. D. chemical element.
mineral
Most gems are A. rocks. B. organic. C. minerals. D. synthetic.
minerals.
A natural material that’s made up of a mass of one or more kinds of mineral crystals is a A. rock. B. group. C. variety. D. chemical element.
rock.
Which of the following is amorphous? A. Beryl B. Amber C. Garnet D. Jadeite
Amber
A broad gem category based on chemical composition and crystal structure is a A. rock. B. group. C. gem variety. D. gem species.
gem species.
Which of the following is a gem variety? A. Beryl B. Garnet C. Andradite D. Demantoid
Demantoid
Which group does almandine belong to? A. Spinel B. Garnet C. Feldspar D. Tourmaline
Garnet
The world’s largest gem-consuming market is A. Japan. B. Europe. C. Thailand. D. United States.
United States
Synthetic gem materials A. are organic. B. are not minerals. C. are usually amorphous. D. are classified as minerals.
are not minerals.
To be a gem, a mineral must be beautiful, durable, and A. rare. B. colorful. C. transparent. D. lightweight.
rare.
Many colored stones are mined by
A. large corporations.
B. massive industrial operations.
C. mechanized systems and heavy equipment.
D. independent miners using small-scale mining methods.
independent miners using small-scale mining methods.
Media attention in the 1990s regarding its treatment reduced consumer confidence in A. spinel. B. emerald. C. rhodolite. D. tanzanite.
emerald.
Most gemstones form in the A. core. B. mantle. C. oceanic crust. D. continental crust.
continental crust.
Rocks altered by heat and pressure are A. granites. B. igneous. C. sedimentary. D. metamorphic.
metamorphic.
Which gem can crystallize in volcanic rock from gasses released by magma? A. Zircon B. Red beryl C. Blue sapphire D. Vietnamese ruby
Red beryl
Which is a key locality for hydrothermal gems? A. Tibet B. Tanzania C. Ouro Preto, Brazil D. Mogok, Myanmar
Ouro Preto, Brazil
Which gem forms by metamorphism? A. Opal B. Red beryl C. Turquoise D. Tanzanite
Tanzanite
Heat and pressure transform limestone into A. opal. B. quartz. C. granite. D. marble.
marble.
A deposit where gems are found in the rock that carried them to the earth’s surface is called A. primary. B. substitute. C. secondary. D. concentrated.
primary.
Which type of deposit is usually the most profitable for colored stone mining? A. Primary B. Hard rock C. Secondary D. Metamorphic
Secondary
Which is a deposit where gems eroded from the source rock and remained in place nearby? A. Eluvial B. Primary C. Alluvial D. Metamorphic
Eluvial
Which is a workable alluvial deposit of gem minerals with economic potential? A. Vein B. Geode C. Placer D. Primary
Placer
Kunzite is most often found in association with A. sapphire in lava. B. moonstone in basalt. C. tourmaline and beryl in pegmatite. D. imperial topaz in hydrothermal veins.
tourmaline and beryl in pegmatite.
Myanmar’s famous Mogok ruby deposits were formed by
A. sedimentary processes.
B. regional metamorphism.
C. gas crystallization from molten lava.
D. mineral-rich solutions close to the earth’s surface.
regional metamorphism
Pegmatite gems are rich in volatile elements like A. chromium and vanadium. B. nickel, copper, and cobalt. C. beryllium, boron, and lithium. D. iron, magnesium, and titanium.
beryllium, boron, and lithium.
Most of the gems in Tanzania’s Umba River Valley are found in A. geodes. B. placer deposits. C. primary deposits. D. hydrothermal gem deposits.
placer deposits.
Emeralds are rarely found in placer deposits because they’re A. too soft. B. too rare. C. chemically unstable. D. unable to withstand much abrasion.
unable to withstand much abrasion.
A unit cell defines a mineral’s A. size. B. habit. C. shape. D. basic identity.
basic identity.
If a crystal grows in a flux that is highly saturated with the necessary elements, it tends to be A. large. B. small. C. terminated. D. well formed.
small.
Which aggregate’s crystals are visible only with magnification greater than a standard gemological microscope’s? A. Mesocrystalline B. Megacrystalline C. Microcrystalline D. Cryptocrystalline
Cryptocrystalline
Which is classified in the orthorhombic crystal system? A. Beryl B. Topaz C. Garnet D. Corundum
Topaz
Which element causes red in ruby and green in emerald? A. Calcium B. Potassium C. Chromium D. Magnesium
Chromium
Which type of twinning is caused by environmental change after the gem forms? A. Cyclic B. Primary C. Penetration D. Polysynthetic
Polysynthetic
Which type of twinning looks as if two crystal halves are mirror images? A. Cyclic B. Contact C. Penetration D. Polysynthetic
Contact
Needles of actinolite found in emerald are classified as A. cleavages. B. inclusions. C. penetration twins. D. impurity elements.
inclusions.
A two-phase inclusion is a cavity in a gem that’s typically filled with a A. pair of liquids. B. gas and a solid. C. liquid and a gas. D. liquid and a solid.
liquid and a gas.
Atoms in a gem that are not part of its essential chemical composition are A. unit cells. B. inclusions. C. trace elements. D. chemical compounds.
trace elements.
The trace elements that cause corundum’s blue are A. iron and titanium. B. chromium and iron. C. aluminum and oxygen. D. aluminum and chromium.
iron and titanium.
An object’s weight in relation to its size is called its A. density. B. carat total. C. atomic index. D. specific gravity.
density.
Which gems are cryptocrystalline aggregates? A. Opal and amethyst B. Nephrite and jadeite C. Sugilite and lapis lazuli D. Chalcedony and turquoise
Chalcedony and turquoise
Rough spinel often occurs as A. twinned crystals. B. tall, columnar crystals. C. microcrystalline aggregates. D. flattened cleavage fragments.
twinned crystals.
Many fashioned rubies have shallow proportions because they’re cut from A. flat crystals. B. tall, columnar crystals. C. heavily included rough. D. flattened cleavage pieces.
flat crystals.
The pattern of dark vertical lines or bands shown by certain gems when viewed through a spectroscope is called A. refraction. B. dispersion. C. pleochroism. D. absorption spectrum.
absorption spectrum.
Which element does chromium substitute for to cause ruby’s red? A. Silicon B. Titanium C. Beryllium D. Aluminum
Aluminum
A gem colored by an element that’s part of its basic chemistry is called A. other-colored. B. allochromatic. C. many-colored. D. idiochromatic.
idiochromatic.
Which element causes the color of both almandine and peridot? A. Iron B. Cobalt C. Titanium D. Chromium
Iron
The process where electrons that selectively absorb light are passed back and forth between neighboring impurity ions is known as A. diffraction. B. interference. C. charge transfer. D. intervalence charge transfer.
charge transfer.
Which components of a transition element’s atoms can produce color in gems? A. Nuclei B. Protons C. Neutrons D. Electrons
Electrons
Which element causes the finest reds and greens in gemstones? A. Iron B. Cobalt C. Chromium D. Magnesium
Chromium
Which transition element causes a greater variety of gem colors than any other? A. Iron B. Cobalt C. Vanadium D. Chromium
Iron
In many blue sapphires, the intervalence charge transfer that causes the color is between A. iron and iron. B. iron and titanium. C. chromium and iron. D. oxygen and oxygen.
iron and titanium.
When a gem’s crystal structure splits light into two rays that each travel at a slightly different speed and direction, it’s called A. diffraction. B. interference. C. single refraction. D. double refraction.
double refraction.
What is the only type of gem that can show pleochroism? A. Faceted B. Phenomenal C. Singly refractive D. Doubly refractive
Doubly refractive
Which gem can show three pleochroic colors? A. Iolite B. Ruby C. Sapphire D. Tourmaline
Iolite
Which phenomenon is a broad color flash? A. Orient B. Iridescence C. Change-of-color D. Labradorescence
Labradorescence
Adularescence is caused by A. dispersion. B. scattering of light. C. selective absorption. D. reflections from inclusions.
scattering of light.
The best-known and most valuable chatoyant gem is cat’s-eye A. zircon. B. quartz. C. tourmaline. D. chrysoberyl.
chrysoberyl.
A laboratory-created gem with essentially the same chemical composition, crystal structure, and properties as its natural counterpart is a(n) A. fake. B. synthetic. C. duplicate. D. imitation.
synthetic.
The two main types of processes for synthetic gem production are melt and A. pulling. B. solution. C. flame fusion. D. floating zone.
solution.
Low cost and high volume characterize which process? A. Pulling B. Flux growth C. Flame fusion D. Hydrothermal growth
Flame fusion
Which synthetic process developed rapidly due to laser research in the 1960s? A. Pulling B. Skull melt C. Flame fusion D. Spontaneous nucleation
Pulling
Which process uses a heating unit to pass over a rotating solid rod of chemicals until it forms a synthetic crystal? A. Skull melt B. Flux growth C. Flame fusion D. Floating zone
Floating zone
Which process dissolves nutrients in chemicals to form synthetic crystals? A. Ceramic B. Flux growth C. Floating zone D. Hydrothermal growth
Flux growth
The crucibles that work best for flux growth are made of A. gold. B. silver. C. titanium. D. platinum.
platinum.
The hydrothermal growth process is the only method used to produce which synthetic gem? A. Opal B. Quartz C. Alexandrite D. Green chrysoberyl
Quartz
Which synthetic process uses an autoclave? A. Pulling B. Skull melt C. Flux growth D. Hydrothermal growth
Hydrothermal growth
Synthetic opal is grown using microscopic silica spheres that are produced by A. pulling. B. sublimation. C. precipitation. D. spontaneous nucleation.
precipitation.
Which process involves heating finely ground powder, sometimes under pressure, to produce a fine-grained solid material? A. Ceramic B. Sublimation C. Precipitation D. Spontaneous nucleation
Ceramic
Synthetic turquoise is most likely produced by which process? A. Pulling B. Ceramic C. Sublimation D. Floating zone
Ceramic
The flux used in the flux process is a solid material that, when molten,
A. dissolves other materials.
B. acts as a pattern for crystal growth.
C. helps prevent the formation of inclusions.
D. produces straight growth patterns in synthetic gems.
dissolves other materials.
The hydrothermal synthetic process requires a
A. chemical flux and platinum crucible.
B. high-temperature flame and powdered feed chemicals.
C. rod of solid ingredients and a high-temperature heating coil.
D. pressurized steel container and crushed chemical ingredients.
pressurized steel container and crushed chemical ingredients.
A snakeskin structural pattern is typical of A. synthetic opal. B. imitation lapis lazuli. C. flame-fusion synthetics. D. hydrothermal synthetic quartz.
synthetic opal.
Which of these is considered a gem treatment? A. Cutting B. Polishing C. Fashioning D. Fracture filling
Fracture filling
Written information on dyeing gems dates back to about A. 200 BC. B. 100 AD. C. 300 AD. D. 700 AD.
200 BC.
Which gem is commonly heat-treated? A. Iolite B. Amber C. Tsavorite D. Rhodolite
Amber
Heat can lighten amethyst’s purple by A. dissolving rutile. B. affecting titanium impurities. C. affecting chromium impurities. D. causing changes in color centers.
causing changes in color centers.
Creating asterism with heat treatment is most common in A. natural ruby. B. natural sapphire. C. synthetic corundum. D. natural fancy sapphire.
synthetic corundum.
What coloring agents do treaters use during lattice diffusion to create a shallow layer of blue color in corundum? A. Cobalt and iron oxide B. Chromium and iron oxide C. Titanium oxide and iron oxide D. Titanium oxide and chromium
Titanium oxide and iron oxide
How deep is the color layer that lattice diffusion with titanium or chromium creates in corundum? A. 0.01 mm to 0.50 mm B. 0.50 mm to 1.00 mm C. 1.00 mm to 1.50 mm D. 1.50 mm to 2.00 mm
0.01 mm to 0.50 mm
What agent can create a shallow layer of asterism when it’s introduced below the surface of a corundum cabochon by lattice diffusion? A. Iron oxide B. Chromium C. Titanium oxide D. Aluminum oxide
Titanium oxide
For effective clarity enhancement, the material used to fill a gem’s fractures must have nearly the same A. color as the gem. B. density as the gem. C. hardness as the gem. D. refractive index as the gem.
refractive index as the gem.
After irradiation, which gem’s color is stable under normal wearing conditions? A. Golden beryl B. Orangesapphire C. Yellow sapphire D. Green spodumene
Golden beryl
Jadeite is often A. irradiated. B. irradiated and annealed. C. surface-diffusion treated. D. bleached and polymer impregnated.
bleached and polymer impregnated.
The Zachery method is a treatment applied to A. jadeite. B. turquoise. C. lapis lazuli. D. cultured pearl.
turquoise.
Heat treatment in a reducing environment A. creates golden color in beryl. B. lightens blue color in sapphire. C. deepens blue color in sapphire. D. deepens red color in tourmaline.
deepens blue color in sapphire.
Quartz or topaz with a thin layer of gold deposited on the surface is known as A. lemon. B. smoky. C. Madeira. D. aqua aura.
aqua aura.
Treaters use sugar treatment to enhance A. opal. B. amber. C. jadeite. D. lapis lazuli.
opal.
What is Myanmar’s most important gem export? A. Ruby B. Spinel C. Jadeite D. Sapphire
Ruby
Which location produces the majority of rubies that end up in mass-produced jewelry? A. Pailin B. Mogok C. Bo Phloi D. Mong Hsu
Mong Hsu
Which trade term describes a mixture of gem qualities that represents unsorted production from a particular mine? A. Mine run B. Mine grade C. Mine mixture D. Mine assortment
Mine run
Which term describes a specific rough gemstone quality range, usually determined by color, size, clarity, and price? A. Grade B. Mine lot C. Mine run D. Mine production
Grade
Where is rough from Mogok brought into Thailand? A. Pailin B. Mae Sai C. Mae Sot D. Bo Phloi
Mae Sot
Where is rough from Mong Hsu brought into Thailand? A. Pailin B. Mae Sai C. Mae Sot D. Bo Phloi
Mae Sai
In mining terms, the theft of a mine’s production by its workers is known as A. picking. B. cobbing. C. low grading. D. high grading.
high grading.
Which of the following is a quantity of stones, sometimes of similar size and quality, from a single mine or from many different sources? A. Parcel B. Mine lot C. Mine run D. Production run
Parcel
Which of these is a cutting center for colored stones in Thailand? A. Pailin B. Mogok C. Mong Hsu D. Chantaburi
Chantaburi
Materials cut free-size are usually A. synthetics. B. manmade imitations. C. large, important stones. D. commercial-quality gems.
large, important stones.
Gemstone sizes cut to fit standard mountings are known as A. free sizes. B. designer cuts. C. industry sizes. D. calibrated sizes.
calibrated sizes.
The market sector where better-quality gemstones are used in well-finished, moderately priced jewelry is known as the A. mass market. B. middle market. C. high-end market. D. commercial market.
middle market.
Which term describes a random sample from a parcel of gemstones, often used to assess the parcel’s overall quality? A. Cut B. Lot C. Pick D. Grade
Cut
Which of the following is a price for buying an entire parcel of gems, or a substantial part of it? A. Lot price B. Cut price C. Pick price D. Grade price
Lot price
Which of the following is a premium price for selecting stones from a parcel? A. Lot price B. Pick price C. Grade price D. Parcel price
Pick price
Which gemstone occurs in almost every color? A. Peridot B. Turquoise C. Tourmaline D. Lapis lazuli
Tourmaline
The first impression of an object’s basic color is its A. hue. B. tone. C. saturation. D. bodycolor.
hue.
Generally, cool-colored hues with low saturation look A. bluish. B. grayish. C. brownish. D. yellowish.
grayish.
Use trade terms that imply geographic origin only if the
A. color is typical of the source.
B. gem’s actual source is known.
C. clarity is typical of the source.
D. color and clarity are typical of the source.
gem’s actual source is known.
Which trade term describes certain tourmalines? A. “Paraíba” B. “Kashmir” C. “Sandawana” D. “Mozambique”
“Paraíba”
Which abbreviation does the GIA Colored Stone Grading System use for a slightly purplish red hue? A. pR B. spR C. slpR D. stpR
slpR
In practice, what GIA Colored Stone Grading tone levels apply to grading transparent colored stones? A. 1 through 11 B. 2 through 6 C. 2 through 8 D. 2 through 10
2 through 8
A see-through area in a transparent gemstone’s bodycolor that usually results from the way the gem was cut is called A. extinction. B. a window. C. color zoning. D. color banding.
a window.
A window usually differs from the rest of the stone in A. hue. B. tone. C. saturation. D. hue and tone.
saturation.
Extinction results from A. mixed cuts. B. deep pavilions. C. shallow proportions. D. excellent proportions.
deep pavilions.
The color of the background for grading a colored stone should be A. dark. B. bright. C. neutral. D. the same hue as the gem.
neutral.
What type of lighting is best for grading color in a colored stone? A. Halogen B. Incandescent C. High red content D. Daylight-equivalent fluorescent
Daylight-equivalent fluorescent
Higher levels of saturation are usually found in stones with A. dark to very dark tone. B. very light to light tone. C. very light to medium tone. D. medium to medium-dark tone.
medium to medium-dark tone.
What two coloring agents are usually responsible for color change in gemstones? A. Copper and iron B. Iron and titanium C. Cobalt and titanium D. Chromium and vanadium
Chromium and vanadium
Emission of visible light by a material when it’s exposed to invisible ultraviolet radiation is A. pleochroism. B. color zoning. C. fluorescence. D. color change.
fluorescence.
Which type of rough is usually faceted? A. Opaque B. Translucent C. Transparent D. Highly included
Transparent
To retain as much weight as possible from rare, high-quality rough, cutters would most likely vary A. finish. B. polish. C. proportions. D. facet placement.
proportions.
Removing heavily included sections from gemstone rough by carefully tapping it with a small hammer is known as A. cabbing. B. cobbing. C. grinding. D. polishing
cobbing.
Rough that’s ground to the approximate shape of the finished stone is called A. preform. B. crown cut. C. pavilion cut. D. ground rough.
preform.
Which is most likely to undergo cobbing? A. Fine-quality ruby rough B. Fine-quality emerald rough C. Fine-quality alexandrite rough D. Commercial-quality amethyst rough
Commercial-quality amethyst rough
Which cutting stage has the greatest impact on the value of the finished gem? A. Sawing B. Cobbing C. Polishing D. Preforming
Preforming
Which colored stone variety has cutting challenges due to vulnerable cleavage planes? A. Tsavorite B. Tanzanite C. Rhodolite D. Alexandrite
Tanzanite
Translucent to opaque rough is often cut into a A. step cut. B. buff-top. C. cabochon. D. brilliant cut.
cabochon.
Which is a carved design that projects slightly from a flat or curved surface? A. Cameo B. Intaglio C. Buff-top D. Sugarloaf
Cameo
Colored stones cut flat with shallow pavilions usually have areas of lower color intensity called A. windows. B. brilliance. C. extinction. D. dispersion.
windows.
A cutter can darken the color of a pale stone by cutting a A. large table. B. deep pavilion. C. shallow crown. D. shallow pavilion.
deep pavilion.
To judge brilliance, view the stone A. face-up. B. in profile. C. table-down. D. pavilion-up.
face-up.
The purpose of most variations in a colored stone’s face-up outline is to A. save weight. B. reduce extinction. C. increase brilliance. D. reduce windowing.
save weight.
Excessive bulge on a step cut A. adds weight. B. adds beauty. C. increases brilliance. D. makes mounting easier.
adds weight.
Colored stones that rate “fair” for brilliance have
A. less than 25 percent brilliance.
B. between 25 and 40 percent brilliance.
C. between 40 and 60 percent brilliance.
D. between 60 and 75 percent brilliance.
between 25 and 40 percent brilliance.
A characteristic or irregularity confined to the surface of a polished gemstone is a(n) A. cavity. B. blemish. C. fracture. D. inclusion.
blemish.
An angular, hollow space that resembles a mineral inclusion is called a A. needle. B. crystal. C. pinpoint. D. negative crystal.
negative crystal.
A general term for a break in a stone is A. chip. B. cavity. C. feather. D. fingerprint.
feather.
An inclusion with the most negative impact on a colored stone’s clarity would be located A. near the girdle. B. under the table. C. under a crown facet. D. under a crown main.
under the table.
In which colored stone clarity type are the gems usually eye-clean? A. Type I B. Type II C. Type III D. Type IV
Type I
The highest clarity grade for colored stones is A. flawless. B. eye-clean. C. internally flawless. D. very very slightly included.
eye-clean.
The term “silk” describes A. intersecting fractures. B. intersecting scratches. C. a group of included crystals. D. a group of fine, needle-like inclusions.
a group of fine, needle-like inclusions.
Fingerprints are A. pits. B. fractures. C. blemishes. D. partially healed fracture planes.
partially healed fracture planes.
Which of these gems is classified as Type III? A. Ruby B. Topaz C. Emerald D. Chrysoberyl
Emerald
In which of the following colored stone clarity grades do the definitions vary for each clarity type? A. Eye-clean B. Heavily included C. Severely included D. Moderately included
Moderately included
Which of these clarity characteristics would usually have the greatest impact on a gem’s marketability?
A. A cavity on its pavilion
B. A large, unhealed feather
C. A small, dark crystal under its crown facets
D. A low-relief liquid inclusion under its table
A large, unhealed feather
Gems that are usually eye-clean include
A. peridot, spinel, and quartz.
B. ruby, alexandrite, and andalusite.
C. spodumene, yellow beryl, and aquamarine.
D. red beryl, emerald, and watermelon tourmaline.
spodumene, yellow beryl, and aquamarine.
Inclusions are important to gemologists because they
A. usually increase a gem’s value.
B. usually create attractive phenomena.
C. always identify a gem’s geographic origin.
D. can help separate natural from synthetic gems.
can help separate natural from synthetic gems.
Growth zoning in a colored stone is evidence of A. fashioning. B. heat treatment. C. crystal growth. D. fracture filling.
crystal growth.
Two factors that determine an inclusion’s impact on a gem’s value are A. size and shape. B. position and relief. C. location and shape. D. crystal system and size.
position and relief.
A gem’s price divided by its carat weight is called A. lot price. B. parcel price. C. per-carat price. D. total gem price.
per-carat price.
The international unit of measurement for gem weight is the A. gram. B. ounce. C. troy ounce. D. metric carat.
metric carat.
Individual stone prices are referred to as A. unit prices. B. parcel prices. C. per-carat prices. D. total gem weight prices.
unit prices.
How many points are in a metric carat? A. 10 B. 50 C. 100 D. 1000
100
A metric carat equals A. 0.20 gram. B. 0.50 gram. C. 1 gram. D. 10 grams.
0.20 gram.
Most colored stones are sold A. by size. B. by shape. C. per piece. D. by weight.
by weight.
What category of colored stone is often sold per piece? A. Large B. Free-size C. Expensive D. Small, inexpensive
Small, inexpensive
Sieves are most useful for sorting round gems with diameters A. 3 mm and below. B. 8 mm and below. C. 15 mm and below. D. 20 mm and below.
3 mm and below.
When you first start to count a large pile of small gems, it’s best to separate them into groups of A. 5. B. 8. C. 17. D. 30.
5.
The color of a sorting pad should be A. dark. B. vivid. C. neutral. D. intense.
neutral.
Colored stones with higher values usually have
A. dark to very dark tone and strong saturation.
B. very light to light tone and strong saturation.
C. very light to medium tone and strong saturation.
D. medium to medium-dark tone and vivid saturation.
medium to medium-dark tone and vivid saturation.