Review Questions for Lecture 11: Mantle Minerals; Pyroxene

1. Describe the crystal structure of pyroxene.
    Draw a cross section looking down the 'c' axis.
    Where does pyroxene cleave? Why?

    Do the same for an amplibole.

2. How does an orthopyroxene differ from a clinopyroxene?

3. What is exsolution?

4. What can geologists determine from two different compositions of
    pyroxenes that coexist?

5. What are primary similarities between pyroxenes and amphiboles?
    What are the differences?

6. Why are the cleavage angles different?

7. Draw a pyroxene and amphibole quadralateral. Label the orthorhombic
    and monoclinic fields.