# 3.9 Learning outcomes for Section 3

Now you have completed this section, you should be able to:

- summarise the range of silicate mineral structures in terms of various degrees of SiO4 polymerisation
- outline the essential structural features of the common rock-forming minerals: olivine, garnet, pyroxene, amphibole, mica, quartz and feldspar
- give examples of some physical properties of minerals that can be attributed to specific crystal structural features
- describe the basic chemistry and properties of common rock-forming minerals in the Digital Kit
- describe the distinguishing features of the major rock-forming minerals in hand specimen and thin section.

Now try the following questions to test your understanding of Section 3.

## SAQ 9

The structure of quartz is built entirely of SiO4 units. Why, then, is its chemical formula SiO2?

## SAQ 10

Quartz and mica are both silicate minerals, but they have very different cleavage properties. How do quartz and mica differ in this respect, and why?

## SAQ 11

What is meant by solid solution? Give two examples of important rock-forming minerals that exhibit solid solution.

OpenLearn - An introduction to minerals and rocks under the microscope
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