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Colored Stones Exam > GIA Colored Stones Exam 1-50 > Flashcards

GIA Colored Stones Exam 1-50 Flashcards

1
Q

Velvety blue to violetish blue; in medium to medium_dark tones; with strong to vivid saturation.

A

fine sapphire

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2
Q

What trace elements cause the blue of sapphire?

A

iron and titanium

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3
Q

A smoky corundum that turns blue when treated is called _______ .

A

Dhun

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4
Q

True or False: Higher levels of iron make basalt_hosted sapphires darker than non_basaltic sapphires.

A

TRUE

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5
Q

What is the trade name considered as the finest blue sapphire?

A

Kashmir

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6
Q

Is color zoning a common sapphire characteristic?

A

Yes

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7
Q

True or False: Most sapphires are heat treated to improve their appearance.

A

TRUE

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8
Q

True or False: Fine quality; untreated sapphires make up a small but extremely valuable segment of the sapphire market.

A

TRUE

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9
Q

What country buys about half of the blue sapphires on the world market?

A

USA

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10
Q

Kashmir sapphires owe their reputation to a brief period of output during what time period?

A

1880’s

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11
Q

What country is a major center of the corundum trade; funneling a steady flow of gems from worldwide sources into the consumer market?

A

Thailand

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12
Q

What country is the world’s largest source of dark blue; commercial quality blue sapphires?

A

Australia

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13
Q

What country has become a significant source of good to fine quality blue sapphires?

A

Madagascar

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14
Q

What is the most common sapphire synthesis method?

A

Flame fusion

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15
Q

A milky; grayish; or brownish corundum that can be treated to a fine blue color is called ________ .

A

Geuda

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16
Q

Blue to violetish blue.

A

Fine blue sapphire

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17
Q

What trace elements cause blue sapphire’s color?

A

titanium and iron.

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18
Q

Blue sapphires that originate in basaltic rock generally have a _________ .

A

higher iron content.

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19
Q

Finer quality Kashmir blue sapphires typically show what type of appearance?

A

Velvety

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20
Q

Type of sapphire described as inky.

A

Australia

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21
Q

Blue sapphire’s most common crystal habit is _________.

A

spindle_shaped hexagonal pyramid or bipyramid.

22
Q

Most fine sapphires of 100 cts. come from what country?

A

Sri Lanka

23
Q

What country emerged in the 1990’s as a significant source of good to fine quality sapphire?

A

Madagascar

24
Q

What country is the world’s largest blue sapphire EXPORTER ?

A

Thailand

25
Q

The sapphire market level supplied by Switzerland is ________ .

A

upper.

26
Q

Kashmir’s most important sapphire production period was from ________ to ________ .

A

1881 to 1887.

27
Q

When did Madagascar become a significant source of blue sapphire?

A

1990’s

28
Q

What location supplies sapphires that are most likely not heat_treated?

A

Yogo Gulch

29
Q

A “Kashmir” sapphire’s blue is also known as _______ .

A

Cornflower blue.

30
Q

A “Burmese” sapphire’s blue is known as ______ blue and is considered somewhat _______ .

A

Royal ; inky

31
Q

The “Ceylon” or “Sri Lanka” sapphire’s saturation is _______ and ________ . The tone is _________ to _________ .

A

grayish and strong saturation; light to medium light tone

32
Q

The “Palin” or “Cambodian” sapphires are typically ______ to _______ in color and look best when fashioned into smaller sizes.

A

violetish blue to slightly greenish blue

33
Q

The “Kanchanaburi” sapphires are less saturated and are generally _______ to _______ in color with a ______ to _________ tone. Minute inclusions cause it to have a grayish appearance.

A

blue to greenish blue color; light to dark tone; similar to Sri Lankan but; not as brilliant

34
Q

Thai sapphires are ________ to _________ in color and often described as _________ or _________ .

A

violetish blue to slightly greenish blue; inky blue or blue_black

35
Q

Australian sapphires often show _____________ plechroism.

A

strong greenish blue

36
Q

Lapis Lazuli is valued for its ___________ and rich ________ color.

A

history ; blue

37
Q

What produces lapis lazuli’s prized royal blue color?

A

lazurite

38
Q

Lapis Lazuli’s value is based on color and the presence or absence of _________ or _________ .

A

calcite or pyrite

39
Q

What 3 treatments are used with lapis?

A

dyed; impregnated with wax or plastic; heated and then dyed

40
Q

What country is the major source for lapis lazuli?

A

Afghanistan

41
Q

What materials have been used as lapis immitations?

A

Glass; plastic and ceramic

42
Q

People value turquoise for it’s combination of what two traits?

A

ancient heritage and attractive color

43
Q

Turquoise is judged by what three factors?

A

color; texture; matrix

44
Q

What is the most prized color of turquoise?

A

intense / uniform /medium blue

45
Q

What element causes turquoise to appear greenish blue?

A

Iron

46
Q

What element causes turquoise to have a pure blue color?

A

Copper

47
Q

What location is the world’s largest producer of turquoise?

A

Southwestern US

48
Q

What country is the major source for top color turquoise?

A

China (Hubai Province)

49
Q

What is the most common turquoise immitation?

A

Plastic

50
Q

The finest grade of lapis lazuli is called ________ .

A

Afghan

Colored Stones Exam (15 decks)

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