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365 Cards in this Set
- Front
- Back
- 3rd side (hint)
Is aquamarine usually treated and why or why not?
|
Aquamarine is almost always heat treated to remove the yellow color component and to produce a more marketable blue color.
|
|
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What is a natural glass gem?
|
Moldavite.
|
Volcanic.
|
|
What is blue sapphires most common crystal habit?
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A spindel-shaped hexagonal pyramid or bipyramid.
|
|
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Define 'maraba amethyst.
|
Less saturated in color, but uniform in color, high clarity in large crystals.
|
|
|
What color is Chrysoprase?
|
Light to medium yellowish green.
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|
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Where is the only place boulder opal is mined?
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Queensland, Northeastern Australia.
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Country and area.
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Where is the major source of both black and white opal?
|
Australia.
|
Country only.
|
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What are the tiny tension cracks in Moonstone called?
|
Centipedes.
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|
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What is moonstone a variety of?
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Orthoclase feldspar.
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What is the greenish blue feldspar that has gridlike white streaks and resembles turquoise called?
|
Amazonite.
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|
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What is Spectrolite a variety of?
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Labradorite.
|
|
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Define 'sun spangles'.
|
Circular marks sometimes left in Amber when treaters heat and oil it.
|
Organic stones.
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Define 'tourmalinated quartz'.
|
A type of sagenitic quartz containing needle-like or rod-like tourmaline inclusions.
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Quartz & Chalcedony.
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Define 'signet'.
|
A table-cut gem with a flat or slightly domed top and sometimes a carved design, typically set in men's rings and cufflinks.
|
Quartz & Chalcedony.
|
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What does precious opal's internal pattern look like?
|
Billions of uniform, submicroscopic silica spheres, stacked in an orderly pattern.
|
|
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Define 'crazing'.
|
The network of tiny fractures that develops when an opal loses moisture.
|
Opal.
|
|
What kind of rock does Turquoise usually form in?
|
Limonite.
|
|
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What are the 2 trace elements responsible for sapphires blue color?
|
Titanium and iron.
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Where was Tanzanite discovered?
|
Merelani, Tanzania, Africa.
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Area, country & continent.
|
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Define 'mountain jade'.
|
Thick-skinned jadeite boulders.
|
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Define 'mottling'.
|
An uneven distribution of color against a contrasting background.
|
Jade.
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Define 'old mine' Jadeite.
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The finest texture category of Jadeite.
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Define 'new mine' Jadeite.
|
The coarsest texture category of Jadeite.
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What is the most common color of untreated, natural Topaz?
|
Colorless.
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|
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Where does most gem quality rough Topaz come from?
|
Pegmatites.
|
Not country source, but growth/rock type.
|
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What color is the finest Aquamarine?
|
Moderately strong, medium-dark blue to slightly greenish blue.
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Define 'watermelon' tourmaline.
|
A tourmaline, usually elbaite, with color zoning made up of a pink central zone surrounded by a green overgrowth.
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|
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What is the most common treatment for Paraiba tourmaline?
|
Heat treatment.
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|
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In what Era was Jet popular in mourning jewelry?
|
The late Victorian Era.
|
|
|
Where is the most important coral-marketing center?
|
Italy.
|
|
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What treatment for turquoise emerged in the 1980's and has treated more than 10 million carats?
|
The Zachery method.
|
|
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Where is the major source of rough for commercial calibrated Peridot?
|
Arizona.
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What trace element must yellow to reddish brown Topaz contain in order to attain a treated pink color?
|
Chromium.
|
|
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Where is the major source for Imperial Topaz?
|
Ouro Preto, Brazil.
|
City & Country.
|
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What is play-of-color called that's only seen when light travels through an Opal to the eye?
|
Contra Luz.
|
|
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What shapes are most common in Tourmalines and why?
|
Slender proportioned emeral or baguette type cuts because of the elongated shape of the crystals.
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What type are most gem Tourmalines?
|
Elbaite.
|
|
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What is the most desireable play-of-color hue?
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Red.
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|
What makes 'boulder opal' more durable than other types?
|
It's matrix backing.
|
|
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What are the 3 characteristics of Opals beauty?
|
Color
Pattern Clarity |
|
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What is the rarest play-of-color?
|
One that contains hues across the entire spectrum.
|
|
|
In Opal, what is the preferred level of transparency?
|
It depends on the background color of the Opal.
|
|
|
What is done to make use of thin Opal pieces?
|
They are assembled into either doublets or triplets.
|
|
|
Where were the first black Opals discovered?
|
New South Wales, Lightning Ridge, Australia.
|
City, Mine & country.
|
|
What is Malachite's color caused by?
|
Copper.
|
Trace element.
|
|
How long ago did Opal deposits form?
|
15 - 30 million years ago.
|
|
|
What is the main composition of Opal?
|
Silica.
|
|
|
What color are the markings of sandstone matrix in Turquoise?
|
Tan.
|
|
|
Define 'Precious' Topaz.
|
A trade term for orange to yellow and brown Topaz.
|
|
|
What treatment is used to turn light-colored or colorless Spodumene into a Kunzite color?
|
Irradiation followed by heat treatment.
|
|
|
Why does Zircon need care in handling and wear?
|
Because of its brittleness.
|
|
|
What country is the world's largest supplier of Tourmaline?
|
Brazil.
|
|
|
Which type of Garnet has the widest color range?
|
Andradite.
|
|
|
Define 'Imperial Jade'.
|
Trade name for finest-quality, semitransparent Jadeite with even, vivid green coloration.
|
|
|
Define 'hololith'.
|
Gemstone jewelry carved entirely from a single piece of rough.
|
Jade.
|
|
Where is the largest supply of Opal mined?
|
Australia.
|
|
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What percentage of the world's supply of Opal is mined in Australia?
|
90%.
|
|
|
Define 'isomorphous replacement'.
|
Substitution of one chemical element for another in the crystal structure of a mineral.
|
|
|
How many cleavage directions are found in Feldspar, Spodumene and Diopside?
|
2 cleavage directions.
|
|
|
What is adularescence caused by?
|
The scattering of light by stacked, alternating mineral layers.
|
|
|
What is the imitation for Sunstone called?
|
Goldstone.
|
|
|
Define 'hollowback'.
|
A cabochon with a curved, undercut bottom, designed to lighten the tone of the gem.
|
Garnet.
|
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Define 'Malaya' Garnet.
|
Pinkish orange Garnet that is a mix of pyrope, spessartite and almandite.
|
|
|
Define 'Ceylon' or 'Sri Lankan' Sapphire.
|
Usually have a slightly grayish to strong saturation and light to medium-light tone.
|
|
|
Define 'Burmese' Sapphire.
|
Usually have a more intense color than Kashmir, sometimes more saturated as well. Also called 'Royal Blue'. Might appear inky under incandescent light.
|
|
|
Define 'Kasmir' Sapphire.
|
Violetish blue to blue, with moderately strong to vivid saturation and a medium-dark tone with a velvety luster. Also called 'Cornflower Blue'.
|
|
|
When was Alexandrite discovered?
|
1830
|
|
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Define 'Spiderweb' Turquiose.
|
Turquiose that contains matrix in think, web-like patterns.
|
|
|
When were the first synthetic flame fusion star Rubies made?
|
1940's
|
Give a decade.
|
|
How old must resin be to be called Amber?
|
At least 1 million years old.
|
|
|
Where is the main polishing center for Jadeite?
|
China.
|
Country.
|
|
What are the 9 colors that Jadeite can be?
|
Green
Lavender Red Orange Yellow Brown White Black Gray |
|
|
What is the most valueable transparency of Jadeite?
|
Semitransparent.
|
|
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What source emerged in the 1990's as a significant source of good to fine quality blue Sapphire?
|
Madagascar.
|
|
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What location supplies blue Sapphires that are most likely not treated?
|
Yogo Gulch, Montana.
|
Mine and state.
|
|
When was Kashmir's most significant production period for blue Sapphire?
|
1881-1887
|
|
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Define 'Padparascha'.
|
Lotus flower; intensely saturated, light to medium pinkish orange to orange-pink Sapphire.
|
|
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Define 'Chilean' Lapis Lazuli.
|
Often tinged or spotted with green, with obvious calcite matrix.
|
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Define 'Russian' or 'Siberian' Lapis Lazuli.
|
Various tones and intensities of blue. Contains pyrite and might contain some calcite.
|
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What is a major source of Cats-eye Chrysoberyl?
|
Sri Lanka.
|
Country.
|
|
What is play-of-color?
|
The interaction of light with Opal's internal structure of stacked silica spheres.
|
|
|
What is the most expensive Opal?
|
Black Opal (Lightning Ridge).
|
|
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Which Opal makes up the bulk of commercial-quality on the market?
|
White Opal.
|
|
|
What is the transparency range of white Opal?
|
Translucent to opaque.
|
|
|
Where was Jadeita first fashioned and used as an ornamental object?
|
China.
|
Country.
|
|
What element causes Jadeite's green color?
|
Chromium.
|
|
|
What are the largest and 2nd largest Ruby exporters?
|
Thailand is first with 61% of its exports shipping to the USA. India is the second largest exporter.
|
|
|
Define 'Geuda'.
|
Milky, grayish or brownish corundum that can be heat treated to a fine blue color.
|
Sapphire.
|
|
What 2 countries produce the finest Peridot?
|
Myanmar & Pakistan.
|
|
|
Where is a major source of Nephrite?
|
New Zealand.
|
|
|
Metamict zircons are also known as what?
|
Low Zircons.
|
|
|
What method is used to produce synthetic Aquamarine?
|
Hydrothermal.
|
|
|
Where is the major source of Turquoise today?
|
Southwestern US.
|
Region.
|
|
What is the most valued color of Emerald?
|
Bluish green to green with strong to vivid saturation and medium to medium dark tone.
|
|
|
What color range is the most valueable Fire Opal in?
|
Uniform red-orange (R/O) to bright red (R).
|
|
|
What colors do color-change Sapphires typically change from and to?
|
From violetish blue to reddish purple.
|
|
|
Which country is the largest producer of Chrome Tourmaline?
|
Tanzania.
|
|
|
Define 'sagenitic' Quartz.
|
Transparent quartz, usually rock crystal, that contains eye-visible inclusions, often named according to the type of inclusions it contains.
|
|
|
Define 'parti-colored'.
|
Gems that show color zoning with 2 or more colors.
|
|
|
What trace element causes Paraiba Tourmaline's colors?
|
Copper.
|
|
|
Which era did Moonstone go out of style in?
|
Art Deco Era, 1920's.
|
|
|
What color is the adularescence in the finest Moonstone?
|
Blue.
|
|
|
Define 'Rubellite'.
|
Trade name for pink to red elbaite Tourmaline.
|
|
|
Define 'Pailin' or 'Cambodian' Sapphire.
|
Generally violetish blue to very slightly greenish blue with medium to dark tone.
|
|
|
How do most gem Tourmalines form?
|
In pegmatites.
|
|
|
Define 'Paraiba' Tourmaline.
|
Trade term for rare, expensive, vibrant green to blue violet elbaite tourmalone, originally found only in Brazil's Paraiba state.
|
|
|
Define 'Egyptian' Turquoise.
|
Greenish blue to yellowish green.
|
|
|
Define the trade term 'Zambian' Emerald.
|
They are slightly darker and more bluish than Columbian Emeralds, often with higher clarity.
|
|
|
Define 'Brazilian' Emerald.
|
Describes Emeralds that are lighter in tone than other Emeralds.
|
|
|
Where is the only commerical source for Charoite?
|
Russia.
|
|
|
What are the 3 elements that cause the color in most fancy Sapphire?
|
Iron
Titanium Chromium |
|
|
What are the 2 main sources for Amber?
|
Baltic Sea
Dominican Republic |
|
|
What are Ruby's pleochroic colors?
|
Red to purplish red in one direction; orangy red in another.
|
|
|
How should a cutter fashion a Ruby to bring out its most appealing pleochroic color?
|
Orient the table facet perpendicular to the long crystal direction.
|
|
|
What colors of Topaz are the rarest and most valueable?
|
Red & pink; including Imperial Topaz.
|
|
|
Where does Peridot sit on the Mohs Scale?
|
6.5 - 7
|
|
|
What types of jewelry is Peridot best used in?
|
Pins, pendants & earrings.
|
|
|
What are the 2 most important Tourmaline treatments?
|
Heating
Irradiation |
|
|
What are the main 4 reason Paraiba Tourmaline commands high prices?
|
Attractiveness
Highly saturated hues Extremely low supply Strong demand |
|
|
What is semi-black Opal's background color?
|
Grayish.
|
|
|
Where is the most important source of Rhodolite in recent years?
|
East Africa.
|
|
|
Where is the major source of Jet?
|
England.
|
|
|
Define 'Imperial' Topaz.
|
A widely used trade term for gem quality Topaz of medium reddish orange to orange-red color.
|
|
|
Where is the world's only source of Bixbite?
|
Wah-wah mountains, Utah.
|
Mine & location.
|
|
What trace element causes the red color of Bixbite?
|
Manganese.
|
|
|
Is Morganite treated and why or why not?
|
Morganite is almost always treated to produce or improve the pink color.
|
|
|
What is the most common number of rays in a star corundum?
|
Six.
|
|
|
Where are Brazilian Emeralds mined from?
|
From pegmatites, where they intersect with schists.
|
Not locale, but rock type.
|
|
Where is the major source of the world's large, fine color Peridot?
|
Myanmar.
|
|
|
Where is the most important source of Rhodolite in recent years?
|
East Africa.
|
|
|
What element causes pink corundum?
|
Manganese.
|
|
|
Where is the major source of Jet?
|
England.
|
|
|
Define 'Imperial' Topaz.
|
A widely used trade term for gem quality Topaz of medium reddish orange to orange-red color.
|
|
|
Where is the world's only source of Bixbite?
|
Wah-wah mountains, Utah.
|
Mine & location.
|
|
What trace element causes the red color of Bixbite?
|
Manganese.
|
|
|
Is Morganite treated and why or why not?
|
Morganite is almost always treated to produce or improve the pink color.
|
|
|
What is the most common number of rays in a star corundum?
|
Six.
|
|
|
Where are Brazilian Emeralds mined from?
|
From pegmatites, where they intersect with schists.
|
Not locale, but rock type.
|
|
Where is the major source of the world's large, fine color Peridot?
|
Myanmar.
|
|
|
What element causes pink corundum?
|
Manganese.
|
|
|
Where is the most important source of Rhodolite in recent years?
|
East Africa.
|
|
|
Where is the major source of Jet?
|
England.
|
|
|
Define 'Imperial' Topaz.
|
A widely used trade term for gem quality Topaz of medium reddish orange to orange-red color.
|
|
|
Where is the world's only source of Bixbite?
|
Wah-wah mountains, Utah.
|
Mine & location.
|
|
What trace element causes the red color of Bixbite?
|
Manganese.
|
|
|
Is Morganite treated and why or why not?
|
Morganite is almost always treated to produce or improve the pink color.
|
|
|
What is the most common number of rays in a star corundum?
|
Six.
|
|
|
Where are Brazilian Emeralds mined from?
|
From pegmatites, where they intersect with schists.
|
Not locale, but rock type.
|
|
Where is the major source of the world's large, fine color Peridot?
|
Myanmar.
|
|
|
What element causes pink corundum?
|
Manganese.
|
|
|
What is the name of Columbia's 3 most famous Emerald mines?
|
Coscuez
La Pita Muzo |
|
|
What is the most common Sapphire synthesis method?
|
Flame fusion.
|
|
|
What do experts think Fire Opal's background color is caused by?
|
Iron impurities.
|
|
|
What is the hue range for Ruby?
|
Orangy red (OR) to purplish red (PR).
|
|
|
What is the top color range for Ruby?
|
Red (R) to slightly purplish red (slpR)
|
|
|
What is the highest saturation and preferred tone for Ruby?
|
Vivid & medium to medium dark.
|
|
|
What is 'Polar Jade'.
|
High quality nephrite.
|
|
|
Define 'reconstructed' Turquoise.
|
A Turquoise imitation made of a mixture of powdered minerals, dyed and bonded with plastic or epoxy resin.
|
|
|
Where is the world's major souce of Lapis Lazuli?
|
Afganistan.
|
|
|
Define 'Burmese' Ruby.
|
The finest hue, tone and saturation. Also called 'Pigeon Blood'.
|
|
|
Define 'Thai' Ruby.
|
Brownish red, purplish red, medium to very dark tone, no fluorescence, black extinction areas. Also called 'Mud Rubies'.
|
|
|
Define 'Ceylon' Ruby.
|
Purplish red, pinkish red, medium to very light tone, brighter. Also known as 'Pink Sapphire'.
|
|
|
What are the 2 types of Coral? Give an example of each.
|
Calcareous... Pink
Conchiolin... Golden |
|
|
What is immature Amber called?
|
Copal.
|
|
|
What color of Amber is the most valueable?
|
Red.
|
|
|
What is the color change in Alexandrite caused by?
|
Chromium.
|
|
|
What is the most valueable color of Coral called?
|
Oxblood Red.
|
|
|
Define 'River Jade'.
|
Weathered, thin-skinned Jadeita boulders.
|
|
|
What color might Jadeite turn if it is heat treated?
|
Orange and reddish colors.
|
|
|
What is the finest quality Jadeite called?
|
Imperial Jade.
|
|
|
Where were the first black Opals discovered?
|
New South Wales, Lightning Ridge, Australia.
|
City, Mine & Country
|
|
What is done to make use of thin Opal pieces?
|
They are assembled into either doublets or triplets.
|
|
|
In Opal, what is the preferred level of transparency?
|
It depends on the background color of the Opal.
|
|
|
What is the transparency range of white Opal?
|
Translucent to opaque.
|
|
|
Which Opal makes up the bulk of commercial quality on the market?
|
White Opal.
|
|
|
Define 'mottling'.
|
An uneven distribution of color against a contrasting background.
|
|
|
What color is Chrysoprase?
|
Light to medium yellowish green.
|
|
|
What color are the markings of sandstone matrix in Turquoise?
|
Tan.
|
|
|
Define 'precious' Topaz.
|
A trade term for orange to yellow and brown Topaz.
|
|
|
What treatment is used to turn light colored or colorless Spodumene into a Kunzite color?
|
Irradiation followed by heat treatment.
|
|
|
Define 'watermelon' Tourmaline.
|
A Tourmaline, usually elbaite, with color zoning made up of a pink central zone surrounded by a green overgrowth.
|
|
|
When was Jet popular in mourning jewelry?
|
Late Victorian era.
|
|
|
What is the most common color of untreated, natural Topaz?
|
Colorless.
|
|
|
What does Precious Opal's interal pattern look like?
|
Billions of uniform, submicroscopic silica spheres, stacked in an orderly pattern.
|
|
|
What kind of rock does Turquoise usually form in?
|
Limonite.
|
|
|
Define 'Chilean' Lapis Lazuli.
|
Often tinged or spotted with green, with obvious calcite matrix.
|
|
|
What is blue Sapphire's most common crystal habit?
|
A spindel-shaped hexagonal pyramid or bipyramid.
|
|
|
Where does most gem quality rough Topaz come from?
|
Pegmatites.
|
How does it grow, rock type.
|
|
What type are most gem Tourmalines?
|
Elbaite.
|
|
|
What color is the finest Aquamarine?
|
Moderately strong, medium-dark blue to slightly greenish blue.
|
|
|
What is adularescence caused by?
|
The scattering of light by stacked, alternating mineral layers.
|
|
|
What is Malachite's color caused by?
|
Copper.
|
|
|
Where is the only place Boulder Opal is mined?
|
Queensland, northeastern Australia.
|
Area & country.
|
|
What treatment for Turquoise emerged in the 1980's and has treated more than 10 million carats?
|
The Zachery Method.
|
|
|
Define 'Tourmalinated' Quartz.
|
A type of sagenitic Quartz containing needle-like or rod-like Tourmaline inclusions.
|
|
|
What is a natural glass gem?
|
Moldavite.
|
|
|
How long ago did Opal deposits form?
|
15 - 30 million years ago.
|
|
|
What is the main composition of Opal deposits?
|
Silica.
|
|
|
Define 'crazing'.
|
The network of tiny fractures that develops when an Opal loses moisture.
|
|
|
Define 'Sun Spangles'.
|
Circular marks sometimes left in Amber when treaters heat and oil it.
|
Organics.
|
|
What is Spectrolite a variety of?
|
Labradorite.
|
|
|
What is play-of-color?
|
The interaction of light with Opal's internal structure of stacked silica spheres.
|
|
|
What is the most expensive Opal?
|
Black Opal from Lightning Ridge.
|
|
|
Define 'signet'.
|
A table cut gem with a flat or slightly domed top and sometimes a carved design, typically set in men's rings and cufflinks.
|
|
|
Define 'Maraba' Amethyst.
|
Less saturated in color, but uniform in color, high clarity in large crystals.
|
|
|
What are the tiny tension cracks in Moonstone called?
|
Centipedes.
|
|
|
Where is the most important Coral marketing center?
|
Italy.
|
|
|
Where was Tanzanite discovered?
|
Merelani, Tanzania, Africa.
|
Area, Country & Continent.
|
|
What are the 2 trace elements responsible for Sapphire's blue color?
|
Iron and titanium.
|
|
|
Why does Zircon need care in handling and wear?
|
Because of its brittleness.
|
|
|
What country is the world's largest supplier of Tourmaline?
|
Brazil.
|
|
|
What is Rhodolite a mixture of?
|
Pyrope and Almandite.
|
|
|
What type of Garnet are both Tsavorite and Hessonite varieties of?
|
Grossularite.
|
|
|
What is Chalcedony with curved or angular bands or layers that differ in color and transparency called?
|
Agate.
|
|
|
What element colors Tsavorite?
|
Vanadium.
|
|
|
What is the smallest crystal size in gemology?
|
Cryptocrystalline.
|
|
|
What does the trade term 'Black Onyx' refer to?
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Treated black Chalcedony.
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Where was the major source of Amethyst in the 19th century found?
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Zambia.
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How is dark Amethyst lightened?
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Heat treatment.
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Where is the major source for commercial Amethyst?
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Brazil.
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Where is the source for natural Ametrine?
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Eastern Bolivia.
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What is Amethyst's most prized color?
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Medium-dark strong reddish purple.
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What is crystalline Quartz known as?
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Chalcedony.
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Where does the majority of Citrine in the market come from?
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Heating Amethyst.
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What are the 3 patterns of play-of-color on Opal?
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Pinfire
Flash Harlequin |
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Which pattern on Opal is the most desireable?
|
Harlequin.
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Define 'Type B' Jadeite.
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Natural Jadeite that's bleached in acid to remove undesireable staining, then impregnated with wax or polymers.
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What is the first step in evaluating an Opal?
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Determining its type.
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Where is the major source for top color Turquoise today?
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China.
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What is the finest color of Turquoise?
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Intense medium blue.
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When was Ivory trading made illegal?
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Mid 1970's.
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Define 'Dhun'.
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Smoky corundum that turns blue when heat treated.
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Sapphire.
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What are blue Sapphires pleochroic colors?
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Slightly greenish blue and slightly violetish blue.
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Are Tourmalines a group or a variety?
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Tourmalines are a group of minerals that share the same crystal structure but have slightly different chemical and physical properties.
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Where do most fine Sapphires over 100 carats come from?
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Sri Lanka.
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What country is the world's largest blue Sapphire exporter?
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Thailand.
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Define 'potch' Opal.
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Opal that lacks play-of-color.
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Define 'matrix'.
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A gem material's host rock, which sometimes becomes part of the finished gem.
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Define 'boulder' Opal.
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Thin layers of Opal, cut to include matrix.
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Define 'Kanchanaburi' Saphhire.
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Blue to slightly greenish blue with light to dark tone. Less saturated stones have a grayish appearance. Most have minute inclusions that give a milky appearance.
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Why do cutters have to pay careful attention to Tourmaline's cut?
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Because Tourmaline has strong pleochroism.
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How are extremely valueable Opal cut?
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To best display their play-of-color.
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What treatment can create a golden color from black Coral?
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Bleaching.
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What easily distinguishes colorless Zircon from Diamond and synthetic Cubic Zirconia?
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Its strong double refraction.
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What country is the largest Ruby importer?
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The US.
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Name 6 main importers of Ruby other than the US.
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Germany, Italy, Taiwan, China, Korea & Hong Kong.
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Other than the US.
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What country is the 2nd largest importer of Rubies, price wise?
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Switzerland.
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What is a major source of black star corundum?
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Australia.
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Which organic shows a structure called 'engine turning' which looks like lines created on a lathe?
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Ivory.
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What is the most prized chatoyant gem in the world?
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Cats-eye Chrysoberyl.
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What do all Garnets share?
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Crystal structure.
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Where is Spessartite usually found?
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Pegmatites.
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Rock growth.
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How much (%) water does most Opal contain?
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3 - 10 percent.
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Define 'Slocum Stone'.
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An Opal imitation made of glass that appeared in the late 1970's.
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What color is Hiddenite?
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Vivid medium green.
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Define 'Thai' Sapphire.
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Violetish blue to slightly greenish blue with medium-dark to dark tone. Also described as inky blue or blue-black.
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Define 'Type A' Jadeite.
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Natural Jadeite enhanced only with a surface coating of wax.
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What element causes the purest blue colors of Turquoise?
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Copper.
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What are the 7 typical characteristic inclusions in Ruby?
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Silk (Rutile needles), boehmite needles, included crystals, fingerprints, growth zoning, color zoning & color banding.
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What is the only Ruby clarity characteristic that has a positive effect?
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Silk.
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Where is the recent source that is the leading producer of small, commercial quality Aquamarine?
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China.
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Where is the most important Aquamarine source?
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Brazil.
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What is Jet an ornamental form of?
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Lignite coal.
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What is responsible for the color of Amethyst?
|
Color centers caused by natural irradiation acting on trace elements of iron in its crystal structure.
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What are the 5 main Ruby treatments?
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Heat treating, fracture & cavity filling, dyeing, quench-crackling & lattice diffusion.
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What is the only accepted form of treatment for Ruby?
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Heat treatment.
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Who created the first marketable synthetic Opal?
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John Slocum.
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What trace element colors Peridot?
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Iron.
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What type of Opal dominates the US market?
|
Commercial quality white Opal.
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What are the 2 methods used to grow synthetic Emeralds?
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Flux & hydrothermal.
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How are commercial grade white and assembled Opal cut?
|
Into standard, calibrated sizes.
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Define 'Agate'.
|
Chalcedony with curved or angular bands or layers that differ in color and transparency.
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What treatment is used to make Zircon blue?
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Heat treament.
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What is the best way to evaluate Opal?
|
By keeping conditions, methods & samples consistant.
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When was Brazil's deposit of Alexandrite discovered?
|
1980
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Define 'stabilized' Turquoise.
|
A trade term for polymer impregnated Turquoise.
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Do Sapphires from basaltic rock have higher or lower iron content?
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Higher iron content.
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What is the type of matrix found as a layer in finished boulder Opal?
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Ironstone.
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What are the 3 cuts most widely used for Topaz and why?
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Elongated ovals, pears & emerald cuts because Topaz crystals are elongated.
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What are the 4 main emerald sources?
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Columbia
Brazil Zambia Zimbabwe |
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Define 'relatively old mine' Jadeite.
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The medium texture category of Jadeite.
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What is the most convincing Tanzanite simulant?
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Synthetic Forsterite.
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Where is the major source of Fire Opal?
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Mexico.
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Which element increases the amount of blue in an Emerald's color?
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Iron.
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What is Tanzanite's best color?
|
Strongly saturated blue or violetish blue.
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What causes the chatoyancy in Cats-eye Quartz?
|
Multiple slender crystals.
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Define 'Type C' Jadeite.
|
Natural Jadeite that has been dyed and often bleached and impregnated with wax or polymers.
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What city is the center of the Jadeite mining district in Myanmar?
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Hpakan.
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What size of crystals make up Tiger's Eye?
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Microcrystalline.
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What causes the asterism in black star Sapphire?
|
Hematite.
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What is the highest transparency star Sapphire should have for best quality?
|
Semi-transparent.
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How do cutters orient the table to emphasize the most desireable color in Emeralds?
|
So the table is perpendicular to the crystal growth.
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What is the term 'spinach' Jade used to describe?
|
Nephrite's green color.
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What is the best way to clean Peridot and why?
|
In warm soapy water because it is sensitive to rapid temperature changes and chemicals.
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Define 'Paua'.
|
The Maori name for abalone shell.
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Organics.
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What is the imitation for Sunstone called?
|
Goldstone.
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Which type of Garnet has the widest color range?
|
Andradite.
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Define 'hololith'.
|
Gemstone jewelry carved entirely from a single piece of rough.
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Where is the largest supply of Opal mined?
|
Australia.
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What percentage of the world's Opal supply is in Australia?
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90%
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Where is the major source of rough for commercial calibrated Peridot?
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Arizona.
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What trace element must yellow to reddish brown Topaz contain in order to attain a treated pink color?
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Chromium.
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What country is the major source of Imperial Topaz?
|
Ouro Preto, Brazil.
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Mine & Country.
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What is play-of-color called that is only seen when light travels through an Opal to the eye?
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Contra Luz.
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What shapes are most common in Tourmalines and why?
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Slender proportioned emerald or baguette type cuts because of the elongated shape of the crystals.
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What is the most desireable play-of-color hue?
|
Red.
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What makes 'boulder' Opal more durable than other types of Opal?
|
The matrix backing.
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What are the 3 characteristics of Opal's beauty?
|
Color
Pattern Clarity |
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What is the rarest play-of-color?
|
Contains hues across the entire spectrum.
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What are the 3 imitations used for Lapis?
|
Glass
Plastic Ceramic |
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What are the 3 treatments used for Lapis?
|
Dyed
Wax or polymer impregnated Heated then dyed |
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Define 'Persian Blue' Turquoise.
|
Robin's egg blue.
|
Color name.
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Define 'Chrome' Tourmaline.
|
Trade term for a vibrant green Tourmaline that is colored by traces of vanadium, chrome, or both.
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What is Rainbow Moonstone a trade name for?
|
Labradorite.
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What are the 3 basic chemical elements all Feldspars have in common?
|
Silicon
Aluminum Oxygen |
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What are the 5 processes for creating synthetic Sapphire?
|
Flame fusion
Flux Pulling Floating Zone Hydrothermal |
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What are the 7 types of Opal?
|
Black
White Crystal Water Boulder Fire Assembled |
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What color range does the highest valued Sapphire fall into?
|
Blue to violetish blue.
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Define 'Tanavyte'.
|
Trade name for purple synthetic YAG as a Tanzanite simulant.
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|
|
What are the 3 imitations used for Lapis?
|
Glass
Plastic Ceramic |
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What are the 3 treatments used for Lapis?
|
Dyed
Wax or polymer impregnated Heated then dyed |
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|
Define 'Persian Blue' Turquoise.
|
Robin's egg blue.
|
Color name.
|
|
Define 'Chrome' Tourmaline.
|
Trade term for a vibrant green Tourmaline that is colored by traces of vanadium, chrome, or both.
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|
What is Rainbow Moonstone a trade name for?
|
Labradorite.
|
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|
What are the 3 basic chemical elements all Feldspars have in common?
|
Silicon
Aluminum Oxygen |
|
|
What are the 5 processes for creating synthetic Sapphire?
|
Flame fusion
Flux Pulling Floating Zone Hydrothermal |
|
|
What are the 7 types of Opal?
|
Black
White Crystal Water Boulder Fire Assembled |
|
|
What color range does the highest valued Sapphire fall into?
|
Blue to violetish blue.
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|
Define 'Tanavyte'.
|
Trade name for purple synthetic YAG as a Tanzanite simulant.
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|
What is Iolite's most valueable face-up color?
|
Blue.
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|
What are the 2 causes of color in most Topaz?
|
Color centers & chromium.
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What treatments are used to create blue Topaz?
|
Radiation & heat treament.
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Why do cutters pay extra attention to cutting, polishing, mounting & wear of Topaz.
|
Because of Topaz's basal cleavage.
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Rubellite Tourmaline is colored by what trace element?
|
Manganese.
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What treatment lightens many green and blue Tourmalines?
|
Heat treatment.
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|
What is the estimated percentage of fracture filled emeralds?
|
90% or more.
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|
What 2 countries account for 75% of Emerald purchases worldwide?
|
US
Japan |
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|
What 2 elements color rare natural blue Spinel?
|
Cobalt & iron.
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What are the 3 elements that are responsible for Emerald's color?
|
Chromium
Vanadium Iron |
|
|
Define 'background color'.
|
An Opal's bodycolor, independent of its play-of-color.
|
Opal.
|
|
Plastic imitation Opal was first marketed in the late 1980's in what country?
|
Japan.
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|
Define 'show points'.
|
Spots of color near the surface of a Jadeite boulder, where the skin is thin enough to allow color to show through.
|
Jadeite.
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|
What element colors red Spinel?
|
Chromium.
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|
How are Zambian Emerald crystals usually shaped?
|
Irregularly.
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|
Who produced a hydrothermal synthetic Emerald layer over faceted Beryl seeds in the 1960's?
|
Johann Lechleitner.
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|
|
What is the treatment called that involves immersing Opal in concentrated sulfuric acid?
|
Sugar treatment.
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|
|
What is the most common Emerald simulant?
|
Synthetic Spinel triplets.
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|
|
When was the Sandawana mine discovered?
|
1950's
|
Emerald.
|
|
When were Emeralds discovered in Zambia?
|
1930's
|
|
|
Define 'Persian' or 'Afghan' Lapis Lazuli.
|
Intense, uniform, medium-dark, slightly violetish blue. Contains little or no pyrite and no calcite.
|
|
|
Where is a main source for Chrome Diopside?
|
Russia.
|
|
|
What treatment is used to create an intense, unstable green color in Spodumene?
|
Irradiation.
|
|
|
What element causes Sapphire's color change?
|
Vanadium.
|
|
|
What is tortoise shell composed of?
|
Protein.
|
|
|
What is the toughness of Jadeite on an exceptional to fair scale?
|
Exceptional.
|
|
|
What color of Jadeite is currently sourced from Guatemala?
|
Black.
|
|
|
Define 'American' or 'Mexican' Turquoise?
|
Light blue, greenish blue to bluish green.
|
|
|
Where were Trapiche Emeralds first discovered?
|
Muzo, Columbia.
|
Mine & Country.
|
|
What are the 2 most popular Sapphire simulants?
|
Glass
Synthetic Spinel & flame fusion Sapphire doublets. |
|
|
Define 'Australian' Sapphire.
|
Violetish blue to very strongly greenish blue with medium-dark to very dark tone. Often show strong greenish blue Pleochroism. Also called inky blue.
|
|
|
Define 'botryoidal'.
|
A crystal growth habit with a bumpy appearance similar to a bunch of grapes.
|
Quartz & Chalcedony
|
|
Define 'Indicolite'.
|
Trade term for blue Tourmaline.
|
|
|
Define 'metamict'.
|
A mineral that has been broken down from a crystalline to a partly amorphous state by emanations from radioactive impurities.
|
|
|
What is the transparency of gray-base black Opal?
|
Opaque.
|
|
|
What produces Lapis Lazuli's prized royal blue color?
|
Lazurite.
|
|