GIA Colored Stones Exam 201-250 Flashcards
An opal with a dark background that is tranparent to semi_transparent and is valued for its strong play_of_color is known as _______ .
Black crystal opal
What gemstone carries thousands of years of cultural significance; especially in Asia?
Jade
Which is more valuable jadeite or nephrite?
Jadeite
What are jadeites three most important qualities?
color; transparency; texture
In addition to green what eight other colors can jadeite be?
lavender; red; orange; yellow; black; white; brown; gray
What is the trade term for the most valuable jadeite?
Imperial
What transparency is the most highly valued jadeite?
Semitransparent
Intense green.
Finest Jadeite
What country is the main polishing center for jadeite?
China
True or False: The intense global demand for jadeite exceeds production?
TRUE
Why are jadeite and nephrite both called jade?
The chemical differences are so subtle.
A readily available; lower_priced alternative to jadeite is ______ .
Nephrite
Gemstone jewelry that is carved from a single piece of rough is called a ________ .
holoith
In jade what is “mottling”?
An uneven distribution of color against a contrasting background
What is mountain jade?
Thick_skinned jadeite boulders
The coarsest texture category of jadeite is known as the term __________ .
new mine
The finest texture category of jadeite is known as the term _______ .
old mine
The term “relatively old mine” refers to what rexture category of jadeite?
medium
Weathered thin_skinned jadeite boulders are known as __________ .
river jade
Spots of color near the surface of a jadeite boulder; where the skin is thin enough to allow color to show through.
show points
What is type A jadeite?
natural jadeite enhanced only with a surface coating of wax.
Natural jadeite that’s bleached in acid to remove undesirable staining; then impregnated with wax or polymers is called __________ .
type C jadeite
In what area was jadeite first fashioned and used as an ornamental object?
Central America
The finest quality jadeite is called __________ .
Imperial jadeite
Jadeite’s finest green color is caused by _______ .
Chromium
The most valuable level of transparency in jadeite is __________ .
semitranpsrent
The toughness of jadeite is _________ .
exceptional
The finest texture category of jadeite is known as _______ .
old mine
What type is bleached and impregnated jadeite?
Type B
What type is dyed jadeite?
Type C
In Myanmar; the center of the jadeite mining district is ____________ .
Hpakan
Spots of color near the surface of a jadeite boulder; where the skin is thin enough to see through; are called ____________ .
show points
What country recently emerged as a valuable source of black jadite?
Guatemala
Polar jade is fine quality __________.
nephrite
What color is caused by the heat treatment of jadeite?
orange
Spinach jade is used to describe a color of ____________ .
nephrite
What country is a major source of nephrite?
New Zeland
What gemstone commands the highest per_carat price of all colored stones?
ruby
Where does ruby rate on the Mohs hardness scale?
9
Red to slightly purplish red; med to med-dark tone; vivid saturation
Finest ruby
What trace element causes ruby to be red?
Chromium
What causes fluorescence in a ruby?
Chromium
In what type of deposits are the finest rubies found?
marble deposits
Basalt_hosted rubies have higher levels of what element?
iron
The iron in basalt_hosted rubies inhibit what?
fuorescence
What is used to treat almost all rubies?
heat
What country IMPORTS the most rubies than any other?
USA
What country is the world’s largest marketing center?
Thailand
What country EXPORTS the most of the faceted commercial_ quality rubies?
Thailand
Switzerland deals with what type of rubies from other countries?
high_end
