Mineralogy 186-210A

Reading guide - Chapter #1

NOTE: This reading guide is intended to reinforce the main points in the assigned reading. Most questions can be answered from Chapter 1 (Klein & Hurlbut). Some questions require additional information, in which case a source is suggested.

Answers to questions contained in this reading guide can be looked up in a separate file.


1. a) Make sure that you understand the different criteria of the scientific definition of a mineral on page 1.

b) Look up the definitions of the following terms . Indicate (by Y or N) which part(s) of the definition of mineral is(are) satisfied, and which substances are "true" minerals.
 
Substance
natural
solid
homogeneous
definite formula
in-organic
highly 

ordered 
mineral

(Y/N)
gold nugget              
cubic zirconia              
obsidian              
natural pearl              
steel              
lodestone              
lava              
iron              
magnesium              
coal              
asbestos              

2. The terms crystal and mineral are used almost interchangeably in this chapter. What is the difference between the two terms (see first paragraph of Chapter 2)? Do minerals include all crystals, or vice-versa?

3. a) What is the law of constancy of interfacial angles?

b) In Figs. 1.3 (page 5) and 2.38 (page 50), this law is illustrated by drawings of crystals of different habits. What is the meaning of "habit" in mineralogy? (Hint: check the index of the textbook for the reference to "habit" in another chapter.)

5. In 1784, Hauy suggested that this law of constancy of interfacial angles reflected the fact that crystals were formed by the stacking of tiny identical building blocks.

a) Did Hauy's conclusion precede or postdate the invention of the microscope? Do you think it would have made a difference? Why?

b) What part of the modern definition of a mineral includes (in different words) the concept proposed by Hauy?

c) Examine Figs. 2.21 and 2.23 (pp. 32-33). Do you see how Hauy's theory explains the variability of habits and constancy of interfacial angles?

6. a) What is the function of a goniometer?

b) Which two types are mentioned on page 3?

c) What are the advantages of each type of goniometer (see pp. 49-50)?

7. What is polarized light (see textbook index)?

8. What technique proved for the first time that crystals display a highly ordered internal arrangement at the atomic scale?

9. Chapter 1 lists a number of properties that have been used over the ages to identify minerals. After reading this chapter, can you match the following dates, properties and instruments?
 
since the Stone Age
colour
electron microprobe
since 1780
light polarization
reflecting goniometer
since 1819
electron microscope
  
since 1912
chemical composition
X-ray diffractometer
since early 1960s
internal order
contact goniometer
since the early 1970s
interfacial angles
human eye

10. Only a few of the chemical elements (e.g. sulfur, silver) we use happen to occur naturally as pure minerals. And only a few minerals are used "as is" (i.e. without major transformation to extract specific elements from them). Why is this the case?

a) Use the "Mineral Index" section of the textbook (pp. 570-583) to find five elements that are known to occur as pure mineral phases.

b) In that same section, can you find some minerals that are used practically "as is" in industry or at home?

11. Several professional or amateur scientific publications on mineralogy are available from the PSE Library, as are different groups devoted to mineral collecting. Here are a few links to resources that will occasionnally be used to supplement the information given in laboratories and lectures.

Scientific journals: American Mineralogist, Canadian Mineralogist

Journals devoted to mineral collecting: Mineralogical Record, Rocks and Minerals