Introduction to Geology

Introduction to Geology

Quiz 2 - Rocks and Minerals

1. A pure chemical substance consisting of one type of atom distinguished by its atomic number is called:
a. an atom.
b. an element.
c. a nucleus.
d. a proton.

2. The number of known elements listed on the Periodic Table is:
a. 64
b. 78
c. 92
d. 108

3. Chemical substances classed as salts are held together by:
a. covalent bonds.
b. ionic bonds.
c. metallic bonds.
d. Van der Waal bonds.
e. none of the above.

4. Isotopes of an element have:
a. the same number of protons and neutrons.
b. the same number of neutrons, but different number of protons.
c. the same number of protons, but different number of neutrons.
d. different numbers of electrons, neutrons, and protons.

5. Density is usually defined as a measure of mass (in grams) divided by the volume (in cubic centimeters, or cm3). What is the average density of seawater?
a. 0.917 grams/cm3
b. 1.0 grams/cm3
c. 1.027 grams/cm3
d. 0.986 grams/cm3

6. What part of the electromagnetic spectrum listed below has the greatest energy (based on highest frequency or shortest wavelength)?
a. UV (ultraviolet rays)
b. visible light
c. thermal infrared rays
d. microwaves
e. radio waves

7. There are 16 elements that are considered most abundant in Earth's physical environment. What two elements are most abundant in Earth's crust?
a. oxygen and silicon.
b. aluminum and iron.
c. hydrogen and oxygen.
d. carbon and oxygen.

8. A substance that in considered a mineral must have which of the following characteristics:
a. It must be naturally occurring in the environment.
b. It must be an inorganic (never living) solid.
c. It must have crystal structure with a definite internal arrangement of atoms.
d. all of the above.

9. What is true about a rock?
a. A rock can be a mixture.
b. A rock may be composed of one or more minerals.
c. A rock may include non-mineral substances, such as water, gases, or organic matter.
d. b and c.
e. all of the above.

10. Rocks are generally classified into what three groups?
a. igneous, sedimentary, and metamorphic
b. minerals, soils, and mixtures
c. weathering, transportation, and deposition
d. igneous, sedimentary, and molten

11. Very few things that are solid are not crystalline. Most naturally occurring, inorganic materials are crystalline substances, having the structure and form of a crystal or is composed of crystals. What is an example of a material that is not a crystalline substance?
a. glass
b. halite
c. fluorite
d. quartz
e. none of the above

12. A crystal structure describes a highly ordered, repeatable arrangement of atoms. Only when molecules are arranged in an orderly, repeatable symmetric pattern will it be considered a mineral. The simplest possible representation of molecule to for a crystal structure is called:
a. a mineral.
b. a unit cell.
c. an octagon.
d. an octagon.

13. Roughly, about how many atoms are in a single crystal grain of salt?
a. 1.2 x 106 (or 1,200,000)
b. 4.5 x 109 (or 4,500,000,000)
c. 13.8 x 109 (or 13,800,000,000)
d. 2.4 x 1018 (or 2,400,000,000,000,000,000)

14. A mineral with the chemical formula of CaCO3 and has a hexagonal or trigonal crystal structure shape is:
a. dolomite.
b. calcite.
c. quartz.
d. gypsum.

15. A crystal system that has crystal shapes that have symmetry axes in equal lengths in 3 directions (at 90º angles to each other) are part of the:
a. trigonal crystal system.
b. isometric crystal system.
c. tetragonal crystal system.
d. triclinic crystal system.

16. The tendency of a crystallized substance (including minerals) to split along definite crystalline planes, yielding smooth surfaces is called:
a. non crystalline.
b. chatoyancy.
c. luster.
d. cleavage.

17. The description of the quality and intensity (sheen or shine) of light reflected off of a mineral, particularly a reflective appearance of the exterior of crystal surfaces is called:
a. luster.
b. fluorescence.
c. specific gravity.
d. double refraction.

18. A mineral that can transmit light, but it is dispersed or cloudy is called:
a. opaque.
b. transparent.
c. translucent.
d. all of the above.

19. Iceland spar is a mineral that can demonstrate double refraction—that is, light passing through clear iceland spar will transmit a double image, or split a laser beam into two separate beams. Iceland spar is a variety of what mineral?
a. quartz
b. calcite
c. feldspar
d. mica

20. According to the Mohs Hardness Scale, which is the hardest mineral?
a. quartz
b. topaz
c. diamond
d. feldspar

21. Many rocks contain minerals that are rich in iron and are partly magnetic and display measurable magnetic susceptibility -- making them useful for geophysical exploration, such as finding hidden faults or mineral ore bodies. A mineral with high magnetic susceptibility includes:
a. magnetite.
b. calcite.
c. calcite.
d. labradorite.

22. The property of a mineral to glow in often bright colors when exposed to invisible ultraviolet radiation (glow under a blacklight) is called:
a. schiller.
b. fluorescence.
c. phosphorescence.
d. thermoluminescence.

23. A geiger counter is used to:
a. count the potential facets on a crystal.
b. count the number of elements in a mineral.
c. measure levels of radioactivity.
d. measure the amount of electricity to move through a rock or mineral.

24. What common mineral fizzes when exposed to mild acid, releasing carbon dioxide gas.
a. calcite
b. quartz
c. feldspar
d. diamond

25. Mafic silicate minerals are rich in magnesium and iron. The word mafic is used to describe rocks containing a group of dark-colored, mainly ferromagnesian minerals (rich in iron and magnesium). Mafic rocks are common in the Earth's crust under the ocean basins and are exposed in the volcanoes of Hawaii and Iceland. Two examples of mafic minerals include:
a. calcite and dolomite.
b. quartz and feldspar.
c. biotite and muscovite.
d. pyroxene and olivine.

26. The minerals orthoclase and plagioclase are examples of what common group of minerals?
a. quartz
b. feldspars
c. micas
d. mafic silicate minerals

27. What silicate minerals have a sheet-like crystal arrangement that allow them to cleve into thin sheets?
a. biotite
b. muscovite
c. clay minerals
d. all of the above

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