CS 12

Question 1

1. Heat treating Mong Hsu rubies
   A. darkens the color.
   B. creates brown overtones.
   C. creates dark centers or cores.
   D. eliminates dark centers or cores.

Answer 1

eliminates dark centers or cores.

Question 2

1. Corundum can only form in an environment that is low in
   A. silicon.
   B. oxygen.
   C. aluminum.
   D. chromium.

Answer 2

silicon

Question 3

1. The flame-fusion method for creating synthetic rubies is also known as
   A. reconstitution.
   B. lead glass filling.
   C. the Verneuil method.
   D. the Chatham method.

Answer 3

the Verneuil method.

Question 4

1. Types of clarity enhancement in ruby include oiling and
   A. bleaching.
   B. irradiation.
   C. glass filling.
   D. lattice diffusion.

Answer 4

Glass filling

Question 5

1. Ruby can command the highest per-carat price of all colored stones, especially when it’s
   A. untreated.
   B. set in platinum.
   C. from Thailand.
   D. cut as a cabochon.

Answer 5

untreated

Question 6

1. Ruby’s major cutting, treatment, and wholesale trading center is
   A. Burma.
   B. Vietnam.
   C. Thailand.
   D. Madagascar.

Answer 6

Thailand.

Question 7

1. Ruby deposits in Thailand and Cambodia are associated with
   A. marble.
   B. granite.
   C. limestone.
   D. alkali basalt.

Answer 7

alkali basalt

Question 8

1. The rubies found in the mountains of Tajikistan, Afghanistan, and Pakistan are all
   A. basalt-hosted.
   B. marble-hosted.
   C. found in alluvial deposits.
   D. enclosed in a dark rock of green zoisite and black amphibole.

Answer 8

marble-hosted

Question 9

1. The most valuable tone and saturation for ruby are
   A. dark tone and strong saturation.
   B. medium tone and strong saturation.
   C. very dark tone and vivid saturation.
   D. medium to medium-dark tone and vivid saturation.

Answer 9

medium to medium-dark tone and vivid saturation.

Question 10

1. Which of the following have inclusions and growth structures that might closely resemble natural rubies?
   A. Red CZ
   B. Melt synthetics
   C. Quench-crackled, dyed quartz
   D. Flux and hydrothermal synthetics

Answer 10

Flux and hydrothermal synthetics

Question 11

1. By the beginning of 2010, which area had emerged as the world’s most important ruby source?
   A. Malawi’s Chimwadzulu Hill
   B. The Umba River Valley of Tanzania
   C. Montepuez in northern Mozambique
   D. The rainforest-covered mountains near Vatomandry, Madagascar

Answer 11

Montepuez in northern Mozambique

Question 12

1. The most common crystal habit for ruby is the
   A. macle.
   B. tetragonal prism.
   C. rhombic dodecahedron.
   D. tabular hexagonal prism.

Answer 12

tabular hexagonal prism

Question 13

1. Rubies that come from marble deposits are typically low in
   A. iron.
   B. oxygen.
   C. chromium.
   D. aluminum.

Answer 13

iron

Question 14

1. Never describe a stone by a source name unless
   A. your employer tells you to.
   B. the stone’s color is typical of that source.
   C. you’re sure the stone came from that source.
   D. it’s the only way your customer will buy the stone.

Answer 14

you’re sure the stone came from that source.

Question 15

1. What location supplied most of the world’s commercial-quality rubies through the 1990s?
   A. Mogok
   B. Bo Rai
   C. Mong Hsu
   D. Umba River Valley

Answer 15

Mong Hsu