1. (a) This sample is composed of 2 major (and several minor) minerals. Name both these abundant minerals and give their formulas.

(b) Briefly describe the texture of this sample.

2. (a) There are at least 5 minerals in this rock. Name THREE of them:

(b) What are most likely to be the dominant cations in the red/purple mineral? What variatal name would you give it? (In other words in part (a) you told me it was a ‘dog’ and now I want to know whether it is a ‘collie’ or a ‘poodle’.)

3. (a) Name at least THREE of the minerals in this rock and tell us how you know that they are what you say they are (correct additional identifications will be worth extra credit).

(b) What characteristic feature is shown by many of the larger pink grains?

4. (a) What are the phenocrysts (big grains) in this rock?

(b) Describe the internal textures shown by most of these phenocrysts.

(c) Assuming that the phase diagram at the right can be applied to this phenocryst phase, label the diagram appropriately and ROUGHLY plot the composition of this mineral.

5. (a) What are the phenocrysts in this rock?

(b) Give a possible composition for this mineral.

6. (a) What silicate mineral comprises most of this hand sample?

(b) To which of the silicate structural groups does this belong?

7. (a) Name the mineral.

(b) What is its chemical formula?

(c) Name another polymorph of this mineral and briefly tell me how these polymorphs differ (What defines the difference between them?).

8. (a) Name the mineral.

(b) What is its chemical formula?

(c) What could this mineral be used for?

9. (a) Name the mineral.

(b) What is its chemical formula?

(c) Part of this sample is armored by basalt. What kind of geologic setting might this sample have come from?

10. (a) Name the mineral.

(b) What is its chemical formula?

(c) Name 2 other members closely related to this sample. i.e. sharing the same basic structure.

11. (a) Name the mineral.

(b) What is its chemical formula?

(c) What is the crystal system of this mineral?

12. (a) Name the yellowish-brown mineral making up most of this sample.

(b) What valuable metal is this mineral mined for?

13. (a) Identify the green mineral in this sample.

(b) What is the major cationic solid solution in this mineral group that controls the color of an individual specimen?

14. (a) What is the Miller Index of the face labeled (a)? How many faces are part of the same form as face (a)?

(b) What is the Miller Index of the face labeled (b)? How many faces are part of the same form as face (b)?

(c) What general conclusion can you state based on your answers to (a) and (b)?

15. (a) Match this wooden block to the appropriate mini-stereographic projection. To which point group and crystal system does this block belong?

(b) BONUS: Summarize the relationship among the blocks in Questions 14 and 15.

16. The grain circle in red gives an optic normal figure. For this grain, determine the birefringence and extinction angle be specific regarding the extinction angle, for example Y ^ cleavage = x°). It’s best to view this grain with the 25x objective.

17. The grain circled in red is a pyroxene which is cut ~normal to the prismatic cleavage (i.e., {110} cleavage). Determine the sign and 2V for this grain. Is this an orthorhombic or a monoclinic pyroxene? Why?

18. Describe, name, and tell me about the origin of the microtexture/structure that you can see in this mineral.

19. (a) What is the atomic occupancy of the unit cell outlined in yellow string?

(b) What is the formula of the mineral?

(c) What is the symmetry of the mineral?

(d) What is the coordination environment surrounding each silver ball?

20. Are the red balls in this model cubic closest packed or hexagonal closest packed? Briefly describe the difference between these two packings.