GIA Colored Stones Exam 1-50

Question 1

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

Answer 1

fine sapphire

Question 2

What trace elements cause the blue of sapphire?

Answer 2

iron and titanium

Question 3

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

Answer 3

Dhun

Question 4

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

Answer 4

TRUE

Question 5

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

Answer 5

Kashmir

Question 6

Is color zoning a common sapphire characteristic?

Answer 6

Yes

Question 7

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

Answer 7

TRUE

Question 8

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

Answer 8

TRUE

Question 9

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

Answer 9

USA

Question 10

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

Answer 10

1880’s

Question 11

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

Answer 11

Thailand

Question 12

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

Answer 12

Australia

Question 13

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

Answer 13

Madagascar

Question 14

What is the most common sapphire synthesis method?

Answer 14

Flame fusion

Question 15

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

Answer 15

Geuda

Question 16

Blue to violetish blue.

Answer 16

Fine blue sapphire

Question 17

What trace elements cause blue sapphire’s color?

Answer 17

titanium and iron.

Question 18

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

Answer 18

higher iron content.

Question 19

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

Answer 19

Velvety

Question 20

Type of sapphire described as inky.

Answer 20

Australia

Question 21

Blue sapphire’s most common crystal habit is _________.

Answer 21

spindle_shaped hexagonal pyramid or bipyramid.

Question 22

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

Answer 22

Sri Lanka

Question 23

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

Answer 23

Madagascar

Question 24

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

Answer 24

Thailand

Question 25

The sapphire market level supplied by Switzerland is ________ .

Answer 25

upper.

Question 26

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

Answer 26

1881 to 1887.

Question 27

When did Madagascar become a significant source of blue sapphire?

Answer 27

1990's

Question 28

What location supplies sapphires that are most likely not heat_treated?

Answer 28

Yogo Gulch

Question 29

A "Kashmir" sapphire's blue is also known as _______ .

Answer 29

Cornflower blue.

Question 30

A "Burmese" sapphire's blue is known as ______ blue and is considered somewhat _______ .

Answer 30

Royal ; inky

Question 31

The "Ceylon" or "Sri Lanka" sapphire's saturation is _______ and ________ . The tone is _________ to _________ .

Answer 31

grayish and strong saturation; light to medium light tone

Question 32

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

Answer 32

violetish blue to slightly greenish blue

Question 33

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.

Answer 33

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

Question 34

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

Answer 34

violetish blue to slightly greenish blue; inky blue or blue_black

Question 35

Australian sapphires often show _____________ plechroism.

Answer 35

strong greenish blue

Question 36

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

Answer 36

history ; blue

Question 37

What produces lapis lazuli's prized royal blue color?

Answer 37

lazurite

Question 38

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

Answer 38

calcite or pyrite

Question 39

What 3 treatments are used with lapis?

Answer 39

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

Question 40

What country is the major source for lapis lazuli?

Answer 40

Afghanistan

Question 41

What materials have been used as lapis immitations?

Answer 41

Glass; plastic and ceramic

Question 42

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

Answer 42

ancient heritage and attractive color

Question 43

Turquoise is judged by what three factors?

Answer 43

color; texture; matrix

Question 44

What is the most prized color of turquoise?

Answer 44

intense / uniform /medium blue

Question 45

What element causes turquoise to appear greenish blue?

Answer 45

Iron

Question 46

What element causes turquoise to have a pure blue color?

Answer 46

Copper

Question 47

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

Answer 47

Southwestern US

Question 48

What country is the major source for top color turquoise?

Answer 48

China (Hubai Province)

Question 49

What is the most common turquoise immitation?

Answer 49

Plastic

Question 50

The finest grade of lapis lazuli is called ________ .

Answer 50

Afghan