IT’S TIME FOR...IT’S TIME FOR...

CRYSTALLOGRAPHYCRYSTALLOGRAPHY

TRIVIA!!TRIVIA!!

RulesRules

Three roundsThree rounds 10 questions per round10 questions per round Pass answers to team to Pass answers to team to

right for gradingright for grading

Round 1 – Question 1Round 1 – Question 1

What is the term to describe a What is the term to describe a crystal that displays crystal that displays imperfectly developed crystal imperfectly developed crystal faces?faces?

Round 1 – Question 2Round 1 – Question 2

Mineral symmetry is manifest by Mineral symmetry is manifest by external symmetry of single crystals external symmetry of single crystals and by internal symmetry of atomic and by internal symmetry of atomic arrangement. arrangement.

What is the main difference between What is the main difference between external and internal symmetry external and internal symmetry elements?elements?

Round 1 – Question 3Round 1 – Question 3

What are the four types of external What are the four types of external symmetry operations? (must know all symmetry operations? (must know all four)four)

Round 1 – Question 4Round 1 – Question 4

Two-fold roto-inversion is equivalent to what other symmetry operation

Round 1 – Question 5Round 1 – Question 5

What is the Herman-Maugin notation for the symmetry operations shown here?

Round 1 – Question 6Round 1 – Question 6Which 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 422

Round 1 – Question 7Round 1 – Question 7

How many crystal classes (point How many crystal classes (point groups) are possible to describe groups) are possible to describe external symmetry? external symmetry?

Round 1 – Question 8Round 1 – Question 8

Rank the six major crystal systems in Rank the six major crystal systems in order of increasing symmetry. order of increasing symmetry.

IsometricIsometric MonoclinicMonoclinic TriclinicTriclinic

Orthorhombic Tetragonal HexagonalOrthorhombic Tetragonal Hexagonal

Round 1 – Question 9Round 1 – Question 9

The point group The point group 4/m32/m 4/m32/m belongs to belongs to what crystal what crystal system?system?

Round 1 – Question 10Round 1 – Question 10

The crystal class (point group) 2/msymmetry shown here belongs to what crystal system?

End of Round 1 End of Round 1

Pass your answers to the team on your Pass your answers to the team on your right for grading. right for grading.

Round 1 – Question 1Round 1 – Question 1

What is the term to describe a What is the term to describe a crystal that displays crystal that displays imperfectly developed crystal imperfectly developed crystal faces?faces?

SubhedralSubhedral

Round 1 – Question 2Round 1 – Question 2

Mineral symmetry is manifest by external Mineral symmetry is manifest by external symmetry of single crystals and by symmetry of single crystals and by internal symmetry of atomic internal symmetry of atomic arrangement. arrangement.

What is the main difference between What is the main difference between external and internal symmetry external and internal symmetry elements?elements?

Internal Symmetry involves Internal Symmetry involves translationtranslation, , external symmetry does notexternal symmetry does not

Round 1 – Question 3Round 1 – Question 3

What are the four types of external What are the four types of external symmetry operations? (must know all symmetry operations? (must know all four)four)

RotationRotation

Reflection (or Mirrors)Reflection (or Mirrors)

Center of SymmetryCenter of Symmetry

Roto-InversionRoto-Inversion

Round 1 – Question 4Round 1 – Question 4

Two-fold roto-inversion is equivalent to what other symmetry operation

Mirror PlaneMirror Plane

Round 1 – Question 5Round 1 – Question 5

What is the Herman-Maugin notation for the symmetry operations shown here?

422422

Round 1 – Question 6Round 1 – Question 6Which is the proper Point Group label (Herman–Maugin notation) for the symmetry operations shown to the left?

4mm 4/m2/m2/m4/m2/m2/m 4/m2/m 422

Round 1 – Question 7Round 1 – Question 7

How many crystal classes (point How many crystal classes (point groups) are possible to describe groups) are possible to describe external symmetry? external symmetry?

3232

Round 1 – Question 8Round 1 – Question 8

Rank the six major crystal systems in Rank the six major crystal systems in order of increasing symmetry. order of increasing symmetry.

TriclinicTriclinicMonoclinicMonoclinicOrthorhombic Orthorhombic Tetragonal Tetragonal Hexagonal Hexagonal IsometricIsometric

Round 1 – Question 9Round 1 – Question 9

The point group The point group 4/m32/m 4/m32/m belongs to belongs to what crystal what crystal system?system?

IsometricIsometric

Round 1 – Question 10Round 1 – Question 10

The crystal class (point group) 2/msymmetry shown here belongs to what crystal system?

MonoclinicMonoclinic