1. IT’S TIME FOR... CRYSTALLOGRAPHY TRIVIA!!

2. Rules
Three rounds
10 questions per round
Pass answers to team to right for grading

3. Round 1 – Question 1
What is the term to describe a crystal that displays imperfectly developed crystal faces?

4. Round 1 – Question 2
Mineral symmetry is manifest by external symmetry of single crystals and by internal symmetry of atomic arrangement.
What is the main difference between external and internal symmetry elements?

5. Round 1 – Question 3
What are the four types of external symmetry operations? (must know all four)

6. Round 1 – Question 4
Two-fold roto-inversion is equivalent to what other symmetry operation

7. Round 1 – Question 5
What is the Herman-Maugin notation for the symmetry operations shown here?

8. Round 1 – Question 6
Which is the proper Point Group label (Herman–Maugin notation) for the symmetry operations shown to the left?
4mm 4/m2/m2/m
4/m2/m

9. Round 1 – Question 7
How many crystal classes (point groups) are possible to describe external symmetry?

10. Round 1 – Question 8
Rank the six major crystal systems in order of increasing symmetry.
Isometric Monoclinic Triclinic
Orthorhombic Tetragonal Hexagonal

11. Round 1 – Question 9
The point group 4/m32/m belongs to what crystal system?

12. Round 1 – Question 10 The crystal class (point group) 2/m
symmetry shown here belongs to what crystal system?

13. End of Round 1
Pass your answers to the team on your right for grading.

14. Round 1 – Question 1
What is the term to describe a crystal that displays imperfectly developed crystal faces?
Subhedral

15. Round 1 – Question 2
Mineral symmetry is manifest by external symmetry of single crystals and by internal symmetry of atomic arrangement.
What is the main difference between external and internal symmetry elements?
Internal Symmetry involves translation, external symmetry does not

16. Round 1 – Question 3
What are the four types of external symmetry operations? (must know all four)
Rotation
Reflection (or Mirrors)
Center of Symmetry
Roto-Inversion

17. Round 1 – Question 4
Two-fold roto-inversion is equivalent to what other symmetry operation
Mirror Plane

18. Round 1 – Question 5
What is the Herman-Maugin notation for the symmetry operations shown here?
422

19. Round 1 – Question 6
Which is the proper Point Group label (Herman–Maugin notation) for the symmetry operations shown to the left?
4mm 4/m2/m2/m
4/m2/m

20. Round 1 – Question 7
How many crystal classes (point groups) are possible to describe external symmetry? 32

21. Round 1 – Question 8
Rank the six major crystal systems in order of increasing symmetry.
Triclinic
Monoclinic
Orthorhombic
Tetragonal
Hexagonal
Isometric

22. Round 1 – Question 9
The point group 4/m32/m belongs to what crystal system?
Isometric

23. Round 1 – Question 10 The crystal class (point group) 2/m
symmetry shown here belongs to what crystal system?
Monoclinic