CS 3

Question 1

1. Which is classified in the orthorhombic crystal system?
   A. Beryl
   B. Topaz
   C. Garnet
   D. Corundum

Answer 1

B. Topaz

Question 2

1. Rough spinel often occurs as
   A. twinned crystals.
   B. tall, columnar crystals.
   C. microcrystalline aggregates.
   D. flattened cleavage fragments.

Answer 2

A. twinned crystals.

Question 3

1. Needles of actinolite found in emerald are classified as
   A. cleavages.
   B. inclusions.
   C. penetration twins.
   D. impurity elements.

Answer 3

B. inclusions.

Question 4

1. Which gems are cryptocrystalline aggregates?
   A. Opal and amethyst
   B. Nephrite and jadeite
   C. Sugilite and lapis lazuli
   D. Chalcedony and turquoise

Answer 4

D. Chalcedony and turquoise

Question 5

1. Which type of twinning is caused by environmental change after the gem forms?
   A. Cyclic
   B. Primary
   C. Penetration
   D. Polysynthetic

Answer 5

D. Polysynthetic

Question 6

1. Crystals that grow in a flux that is highly saturated with the necessary elements tend to be
   A. large.
   B. small.
   C. terminated.
   D. well formed.

Answer 6

B. small.

Question 7

1. A two-phase inclusion is a cavity in a gem that’s typically filled with
   A. a pair of liquids.
   B. a gas and a solid.
   C. a liquid and a gas.
   D. two solids of different colors.

Answer 7

C. a liquid and a gas.

Question 8

1. Which aggregate’s crystals are visible only under very high magnification?
   A. Mesocrystalline
   B. Megacrystalline
   C. Microcrystalline
   D. Cryptocrystalline

Answer 8

D. Cryptocrystalline

Question 9

1. Atoms in a gem that are not part of its essential chemical composition are
   A. unit cells.
   B. inclusions.
   C. trace elements.
   D. chemical compounds.

Answer 9

C. trace elements.

Question 10

1. Many fashioned rubies have shallow proportions because they’re cut from
   A. flattened crystals.
   B. tall, columnar crystals.
   C. heavily included rough.
   D. flattened cleavage pieces.

Answer 10

A. flattened crystals.

Question 11

1. How heavy an object is in relation to its size is called its
   A. density.
   B. carat total.
   C. atomic index.
   D. specific gravity.

Answer 11

A. density.

Question 12

1. The trace elements that cause corundum’s blue are
   A. iron and titanium.
   B. chromium and iron.
   C. aluminum and oxygen.
   D. aluminum and chromium.

Answer 12

A. iron and titanium.

Question 13

1. Which element causes red in ruby and green in emerald?
   A. Calcium
   B. Potassium
   C. Chromium
   D. Magnesium

Answer 13

C. Chromium

Question 14

1. A unit cell defines a mineral’s
   A. size.
   B. habit.
   C. shape.
   D. basic identity.

Answer 14

D. basic identity.

Question 15

1. Which type of twinning looks as if two crystal halves are mirror images?
   A. Cyclic
   B. Contact
   C. Penetration
   D. Polysynthetic

Answer 15

D. Polysynthetic