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Colored Stones-GIA
(part II)
200
Geology
Undergraduate 3
09/19/2011

Additional Geology Flashcards

 


 

Cards

Term

 

 

 

 

Chromium

Definition

 

 

 

 

 

Which element causes red in Ruby and Green in Emerald?

Term

 

 

 

 

Polysynthetic

Definition

 

 

 

Which type of twinning is caused by enviromental change after the gem forms?

Term

 

 

 

 

Contact

Definition

 

 

 

 

Which type of twinning looks as if two crystal halves are mirror images?

Term

 

 

 

 

Vanadium

Definition

 

 

 

 

Sapphire's color change is caused by

Term

 

 

 

 

6

Definition

 

 

 

 

The most common # of rays in Star Sapphire

Term

 

 

 

 

Semi-transparent

Definition

 

 

 

 

Best Corundum

Term

 

 

 

 

1940's

Definition

 

 

 

 

Th 1st flame-fusion Star Rubies were produced in the

Term

 

 

 

 

Red

Definition

 

 

 

 

Which is the most prised bodycolor in Star Corrundum?

Term

 

 

 

 

Chromium

Definition

 

 

 

 

What causes the Pink color Corundum?

Term

 

 

 

Which Fancy Sapphire hue regularly commands top prices?

Definition

 

 

 

Pink

Term

 

 

 

 

Which color Sapphireis usually cut shallow due to parting?

Definition

 

 

 

 

Black

Term

 

 

 A major source of Black Sapphire.

 

 

Definition

 

 

 

 

Australia

Term

 

 

 

 

The name padparadscha means

Definition

 

 

 

 

lotus flower

Term

 

 

 

 

What's a common trade name for intensely saturated, light to medium pinkish orange to orange-pink sapphires?

Definition

 

 

 

 

Padparadscha

Term

 

 

 

 

Color-change sapphire typically changes from blue or violet to

Definition

 

 

 

 

reddish purple

Term

 

 

 

 

Hematite

Definition

 

 

 

 

Asterism in black star sapphirenis caused by

Term

 

 

 

 

Red

Definition

 

 

 

 

Which is the most prized bodycolor in star corundum?

Term

 

 

 

 

readily avaliable

Definition

 

 

 

 

Green sapphire

Term

 

 

 

 

light in tone

Definition

 

 

 

 

Fancy sapphires from Montana tend to be

Term

 

 

 

 

Fish scales and varnish

Definition

 

 

 

 

Essence d'orient is a mixture of

Term

 

 

 

 

Dudley

Definition

 

 

 

 

Largest gem-quality natural pearl

Term

 

 

 

 

Low in saturation

Definition

 

 

 

 

Pearl colors are

Term

 

 

 

 

Peacock

Definition

 

 

 

Tahitian cultured pearls with a dark green-grey, blue-grey rosé purple overtones

Term

 

 

 

 

Pearls with high luster

Definition

 

 

 

 

Mollusks in cooler water

Term

 

 

 

 

Bead nucleus darkens

Definition

 

 

 

 

What happens when saltwater cultured pearls are exposed to gamma rays?

Term

 

 

 

 

Acceptable

Definition

 

 

 

 

Narce quality classification "Nucleus not noticable, no chalky apperance."

Term

 

 

 

 

Good

Definition

 

 

 

 

the matching level that describes a group of pearls that have minor variations in uniformity is

Term

 

 

 

 

Calcium carbonate

Definition

 

 

 

 

Aragonite is a crystalized form of

Term

 

 

 

 

Organic gem

Definition

 

 

 

 

Pearl is

Term

 

 

 

 

1908

Definition

 

 

 

By ____Kokichi Mikimoto begun cultivating whole pearls

Term

 

 

 

 

Australia

Definition

 

 

 

 

was the 1st South Sea Farm

Term

 

 

 

 

Saltwater whole cultured pearls-mantle tissue and a bead nucleus

Definition

 

 

 

 

Freshwater whole cultured pearls-mantle tissue peice only

Term

 

 

 

 

 

1990's

Definition

 

 

 

 

Japanesse pearls die off in massive numbers

Term

 

 

 

 

The Philippines

Definition

 

 

 

 

South Sea cultured pearls are produced principally in Australia, Indonesia and

Term

 

 

 

Aluminum

Definition

 

 

 

 

Which element does chormium substitute for Ruby's red?

Term

 

 

 

 

idochromatic

Definition

 

 

 

 

A gem colored by an element that's part of it's basic chemistry is called

Term

 

 

 

 

Iron

Definition

 

 

 

 

which element causes the color of both almandite and peridot?

Term

 

 

 

 

Charge transfer

Definition

 

 

 

The process where electrons selectively absorb light are passed back and forth between neighboring imputiy ions is known as

Term

 

 

 

 

Electrons

Definition

 

 

 

 

Which components of a transition elements atoms can produce color in gems?

Term

 

 

 

 

Double refraction

Definition

 

 

 

 

When a gems crystal structure splits into two rays that each travel at slightly different speeds and direction, it's called

Term
A gem produced by, or derived from, a living organism is
Definition
Organic
Term
Which of the following is an organic gem?
Definition
Amber
Term
A substance that consists of atoms of only one kind is a
Definition
Chemical element
Term
A natural, inorganic substance with a chemical composition and usually characteristic crystal structure is a
Definition
Mineral
Term
Most gems are
Definition
Minerals
Term
Which of the following is amorphous
Definition
Amber
Term
A broad gem category based on chemical composition and crystal structure is  a
Definition
Gem species
Term
Which of the following is a gem variety?
Definition
Demantoid
Term
Which group does almandite belong to?
Definition
Garnet
Term
The worlds largest gem consuming market is
Definition
United States
Term
Compared to the domestic market for diamonds, the US domestic market for natural, unset, non-diamond gem is
Definition
less a tenth of the size
Term
To be a gem a mineral must be beautiful, durable, and
Definition
rare
Term
Many colored stones are mined by
Definition
independent miners using small-scale mining methods.
Term
Media attention in the 1990's regarding it's treatment reduced consumer confidence in
Definition
Emerald
Term
Most gemstones form in the
Definition
Continental crust
Term
Rocks altered by heat and pressure are
Definition
metamorphic
Term
Which gem can crystalize in volcanic rock from gases released by magma?
Definition
Red beryl
Term
Which is a key locality for hydrothermal gems
Definition
Ouro Preto, Brazil
Term
   Which gem forms by metamorphism?
Definition
Tanzanite
Term
Heat and pressure form limestone into
Definition
marble
Term
A deposit where gems are found in the rock that carried them to the earth's surface is called
Definition
primary
Term
Which type of deposit usually the most profitable for colored stone mining?
Definition
Secondary
Term
Which is a deposit where gems eroded from the source rock and remained in place nearby?
Definition
Eluvial
Term
Which is a workable alluvial deposit of gem minerals with economic potential?
Definition
Placer
Term
Kunzite is most often found in association with
Definition
tourmaline and beryl in pegmatite
Term
Myanmar's famous Mogok ruby deposits were formed by
Definition
regional metamorphism
Term
Pegmatite gems are rich in volatile elements like
Definition
beryllium, boron and lithium
Term
Most of the gems in Tanzania's Umba River Valley are found in
Definition
placer deposits
Term
Emeralds are rarely found in placer deposits because they're
Definition
unable to withstand much abraision.
Term
A unit cell defines a mineral's
Definition
basic identity
Term
If a crystal grows in a flux that is highly saturated with the neccessary elements, it tends to be
Definition
small
Term
Which aggregate's crystals are visible only with a magnification greater then a standard gemological microscope's?
Definition
Cryptocrystalline
Term
Which is classified in the orthorhombic crystal system?
Definition
Topaz
Term
Which type of twinning is caused by enviromental change after the gem forms?
Definition
Polysynthetic
Term
Needles of actinolite found in emerald are classified as
Definition
inclusions
Term
A two-phase inclusion is a cavity in a gem that's typically  filled with a
Definition
liquid and a gas
Term
Atoms in a gem that are not part of it's essential chemical composition are
Definition
trace elements
Term
The trace elements that cause corrundum's blue are
Definition
iron and titanium
Term
An object's weight in relation to it's size is called it's
Definition
density
Term
Which gems are cryptocrystalline aggregates?
Definition
Chalcedony and turquoise
Term
Rough spinel often occurs as
Definition
twinned crystals
Term
Many fasioned rubies have shallow proportions because they are cut fom
Definition
flat crystals
Term
The pattern of dark vertical lines or bands shown by certain gems when viewed through a spectroscope is called
Definition
aborption spectrum
Term
Which element does chromium substitute for to cause ruby's red?
Definition
Aluminium
Term
 What element causes the color of both almandite and peridot?
Definition
Iron
Term
The process where electrons that selectively absorb light are passed back and forth between neighboring impurity ions is known as
Definition
charge transfer
Term
Which components of a transition element's atoms can produce color in gems?
Definition
Electrons
Term
Which element causes the finest reds and greens in gemstones?
Definition
chromium
Term
Which transition element causes a greater variety of gem colors then any other?
Definition
Iron
Term
In many blue sapphires,the intervalence charge transfer that causes the color is between
Definition
iron and titanium
Term
When a gem's crystal structure splits light into two rays that each travel at a slightly different speed and direction, it's called
Definition
double refraction
Term
What is the only type of gem that shows pleochroism?
Definition
Doubly refractive
Term
Which gem can show three pleochroic colors?
Definition
Iolite
Term
Which phenomenon is a broad flash of color?
Definition
Labradorescence
Term
Adularescence is caused by
Definition
scattering of light
Term
The best-known and most valuable chatoyant gem is called cat's-eye
Definition
chrysoberyl
Term
A laboratory-created gem with essentially the same chemical composition, crystal structure, and proportions as it's natural counterpart is a
Definition
synthetic
Term
The two main types of processes for synthetic gem production are melt and
Definition
solution
Term
Low cost and high volume characterize which process?
Definition
Flame fusion
Term
Which synthetic process developed rapidly due to laser research in the 1960's?
Definition
Pulling
Term
Which process uses a heating unit to pass over a rotating solid rod of chemicals until it forms a synthetic crystal?
Definition
Floating zone
Term
Which process dissolves nutrients in chemicals to form sythetic crystals?
Definition
Flux growth
Term
The crucibles that work best for flux growth are
Definition
platinum
Term
The hydrothermal growth process is the only method used to produce which synthetic gem?
Definition
Quartz
Term
Whch sythetic growth process uses an autoclave?
Definition
Hydrothermal growth
Term
Synthetic opal is grown using microscopic silica spheres that are produced by
Definition
precipitation
Term
Which process involves heating finely ground powder, sometimes under pressure, to produce a fine-grained solid material?
Definition
Ceramic
Term
Synthetic turquoise is most likely produced by which process?
Definition
Ceramic
Term
The flux used in the flux process is a solid material that, when molten,
Definition
dissolves other materials
Term
The hydrothermal synthetic process requires a
Definition
pressurized steel container and crushed chemical ingredients.
Term
Which of these is considered a gem treatment?
Definition
Fracture filling
Term
Written information on dyeing gems date back to about
Definition
200 BC.
Term
Which gem is commonly heat-treated
Definition
Amber
Term
Heat can lighten amethyst's purple by
Definition
causing changes in color centers
Term
Creating asterism with heat treatment is most common in
Definition
synthetic corrundum
Term
What coloring agents do treaters using lattice diffusion to create a shallow layer of blue in corrundum?
Definition
Titanium oxide and iron oxide
Term
How deep is the color layer that lattice diffusion with titanium or chromium creates in corrundum?
Definition
0.01 mm to 0.50 mm
Term
Which agent can create a shallow layer of asterism when it's introduced below the surface of a corrundum cabochon by lattice diffusion?
Definition
Titanium oxide
Term
For effective clarity enhancement, the material used to fill a gem's fractures must have nearly the same
Definition
refractive index as the gem
Term
After irradation,which gem's color is stable under normal wearing condition's?
Definition
Golden beryl
Term
Jadeite is often
Definition
bleached and polymer impregnated
Term
The Zachery method is a treatment applied to
Definition
turquoise
Term
Heat treatment in a reducing environment
Definition
deepens blue color in sapphire
Term
Quartz or topaz with a thin layer of gold deposited on the surface is known as
Definition
aqua aqua
Term
Treaters use sugar treatment to enhance
Definition
opal
Term
In pearl culturing, the most difficult shape to produce is
Definition
round
Term
The largest gem-quality natural pearl is known as the
Definition
Dudley
Term
Pearl colors are
Definition
low in saturation
Term
In the trade, Tahitian cultured pearls with a dark green gray to blue grey body color and rosé to purple overtones are called
Definition
peacock
Term
which overtone color increases the value of akoya cultured pearls with white bodycolor?
Definition
Rosé
Term
When mollusks live in cooler water, they form
Definition
pearls with higher luster
Term
Pearls that show noticeable surface characteristics are
Definition
Moderately Blemished
Term
The best way to clean pearls is
Definition
with warm, mild soapy water
Term
The narce quality classification described as "Nucleus not noticeable, no chalky appearance" is
Definition
Acceptable
Term
The matching level that describes a group of pearls that have minor variations in uniformity is
Definition
good
Term
Farmers of every cultured pearl type do at least which of these after harvest?
Definition
Wash, dry and sort
Term
Almost all akoya and Chinese freshwater pearls are
Definition
bleached
Term
Usually, the diameters of the cultured pearls in a husk vary from each other by no more than
Definition
0.5 mm
Term
What happens when saltwater cultured pearls are exposed to gamma rays?
Definition
Bead nucleus darkens.
Term
Pearls are
Definition
an organic gem
Term
Aragonite is a crystallized form of
Definition
calcium carbonate
Term
Which industry directly contributed to the decline of the natural pearl industry?
Definition
Oil
Term
The great majority of freshwater whole cultured pearls grow from a
Definition
mantle-tissue piece only
Term
The four major types of cultured whole pearls are akoya, South Sea, freshwater and
Definition
Tahitian
Term
South Sea cultured pearls are produced princpally in Australia, Indonesia, and
Definition
the Philippines
Term
The oyster used to grow Tahitian cultured pearls is
Definition
Pinctada margaritifera (think piña colada & margarita)
Term
The narceous layer inside a pearl-bearing mollusk's shell is called
Definition
mother-of-pearl
Term
Which country produces the most freshwater cultured pearls?
Definition
China
Term
A number of similar cultured pearl strands bundled together is called a
Definition
hank
Term
Seed pearls are
Definition
very small natural pearls
Term
The most highly valued hues of blue sapphire are
Definition
blue to violetish blue
Term
What trace elements cause blue sapphire's color?
Definition
Titanium and iron
Term
Blue sapphire that originate in basaltic rock generally have
Definition
high iron content
Term
Milky, greyish or brownish corrundum that can be treated to a fine blue color is called
Definition
geuda
Term
Finer-quality Kashmir sapphires typically show
Definition
velvety appearance
Term
Australian blue sapphire color is often described as
Definition
inky
Term
Blue sapphire's most common crystal habit is
Definition
a spindle-shaped hexagonal pyramid or bipyramid
Term
Blue sapphire's pleochroic colors are typically
Definition
slightly greenish blue and slightly violetish blue
Term
Most fine sapphire's over 100cts. come from
Definition
Sri Lanka
Term
Which of the following sources emerged in the 1990's as a significant source of good to fine=quality sapphire?
Definition
Madagascar
Term
The world's largest blue-sapphire exporter is
Definition
Thailand
Term
The sapphire market level supplied by Switzerland is
Definition
upper
Term
Kashmir's most important production period was from
Definition
1881-1887
Term
When did Madagascar become a significant source of blue sapphire?
Definition
1990's
Term
Which location supplies sapphires that are most likely not heat-treated?
Definition
Yogo-Guluch
Term
The most desirable emerald hues are
Definition
bluish green to green
Term
Which element increases the amount of blue in an emerald's color?
Definition
Iron
Term
The trade term "Zambian" describes emeralds with
Definition
more blushish color and darker tone than "Columbian."
Term
Brazilian emeralds are mined from
Definition
hydrothermal deposits
Term
To emphasize the most desirable color, cutters orient a fashioned emerald with it's table
Definition
perpendicular to the crystal's length
Term
What's the estimated percentage of fashioned emeralds that contain filled fractures?
Definition
90 or more
Term
Which two countries account for about 75 percent of emerald purchase worldwide?
Definition
US and Japan
Term
The four major emerald sources are Colombia, Zambia, Brazil and
Definition
Zimbabwe
Term
One of Columbia's traditional emerald mines is called
Definition
Coscuez
Term
Compared to emeralds from other sources, emeralds from African mines
Definition
are less saturated in color
Term
Trapiche emeralds were first discovered in
Definition
Muzo
Term
Emerald's were discovered in Zambia in the
Definition
1930's
Term
Zambian emerald crystals are typically
Definition
irregualr in shape
Term
The Sandawana emerald mine was discovered in the
Definition

1950's

(think "sand and water, 50/50")

Term
Who produced a hydrothermal synthetic emerald layer over faceted beryl seeds in the 1960's?
Definition
Lechleitner
Term
In ancient Sanskrit, ruby is called ratnaraj or
Definition
"King of precious stones."
Term
The most valuable tone and saturation for ruby are
Definition
medium to medium-dark tone and vivid saturation
Term
Corrundum that came from marble deposits are typically low in
Definition
iron
Term
Ruby deposits in Thailand, Cambodia and Madagascar are associated with
Definition
alkali-basalt
Term
Heat treating Mong Hsu rubies
Definition
Eliminates dark centers or cores
Term
The world's largest corrundum marketing center is
Definition
Thailand
Term
Switzerland exports rubies that are primarily
Definition
high end
Term
What location has supplied the world with most commercial-quality rubies since 1991?
Definition
Mong Hsu
Term
In the early 1980's, the major source for rubies was
Definition
Thailand
Term
Compared to rubies from Myammar, most Thai rubies tend to be
Definition
darker
Term
Rubies from Pailian, Cambodia are similar to those from
Definition
Thailand
Term
Vietnamese rubies originate in
Definition
marble
Term
Where are the Penny Lane and John Saul mines located?
Definition
Kenya
Term
Newly discovered ruby deposits at Vatomandy and Andilamena are in what country?
Definition
Madagascar
Term

A gem's price divided by it's carat weight is called

 

Definition
price-per-carat
Term
The international unit of measurement for gem weight is the
Definition
metric carat
Term
Individual stone prices are reffered to as
Definition
unit prices
Term
How many points are in a metric carat?
Definition
100
Term
A metric carat equals
Definition
0.20 gram
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