B.Sc. DEGREE EXAMINATION, NOVEMBER 2017
Third Semester
Geology
CRYSTALLOGRAPHY AND OPTICAL MINERALOGY
(CBCS 2014 onwards)
Time 3 Hours Maximum 75 Marks
Part A (10 x 2 20)
Answer all questions.
1. Define the term crystal.
2. What is meant by face index?
3. Write the symmetry elements of Normal Class of
isometric system.
4. Give the symmetry of wulfenite.
5. Write the symmetry elements of Baryte.
6. Define Twinning. Give an example.
7. What is meant by plane polarized light?
8. Define isotropism.
9. Define optic axis.
10. What are anisotropic minerals?
Sub. Code
4BGE3C1
AFF-4477
2
Wk16
Part B x 5 25)
Answer all questions choosing either
11. Write a note on Weiss zone law nd its applications.
Or
Write a brief note on the symmetry elements of
crystals and their Significance.
12. What are symmetry elements? Add a note on the
symmetry of Zircon Type.
Or
Write a brief note on the symmetry of Hexagonal
rhombohedra division. Give examples.
13. Write a brief note on the symmetry of Olivine.
Or
Write a note on laws of Twinning. Give examples.
14. Write a brief note on Double refraction.
Or
Give Brief note on optical accessories.
15. Write a brief note on uniaxial minerals. Give
examples.
Or
Write a short note on Birefringence and its
determination.
AFF-4477
3
Wk16
Part C x 10 30)
Answer any three questions.
16. Write an essay on derivation of 32 crystal classes.
17. Write an essay on the symmetry elements classes and
forms of Hexagonal systems.
18. Write an essay on the symmetry elements classes and
forms of orthorhombic System.
19. Give a detailed account of petro logical microscope, its
parts and function with a neat sketch.
20. Write an essay on the optical properties of anisotropic
minerals that can be viewed under petro logical
microscope.
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