CRYSTALLOGRAPHYCRYSTALLOGRAPHY

TRIVIATRIVIA

ROUND 2!ROUND 2!

Round 2 – Question 1Round 2 – Question 1

Excluding AB, crystal faces will most likely occur along whichlattice plane?

Round 2 – Question 2Round 2 – Question 2

What does Steno’s Law of Interfacial What does Steno’s Law of Interfacial Angles state?Angles state?

Round 2 – Question 3Round 2 – Question 3

What does the crystal growth illustration to the left indicate?

a) lattice plane a has a higher atomic density than o,

b) Lattice plane o has a higher growth rate than a, or

c) 111 faces are only common in large, mature crystals

Round 2 – Question 4Round 2 – Question 4

The crystallographic axes shown below are indicative of what crystal system?

Round 2 – Question 5Round 2 – Question 5

How are crystallographic axes different between the orthorhombic and tetragonal systems?

Round 2 – Question 6Round 2 – Question 6

What crystal face would qualify as the “unit face” in this orthorhombic crystal? (give face intercepts)

Round 2 – Question 7Round 2 – Question 7

What is the Miller Index for the upper face?

Round 2 – Question 8Round 2 – Question 8

What is the Miller index of the shaded face in this hexagonal crystal?

Round 2 – Question 9Round 2 – Question 9

Faces b, m, and a belong to what zone?

[_ _ _]

Round 2 – Question 10Round 2 – Question 10

What is the form index of the p face?

{_ _ _}

End of Round 2 End of Round 2

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

Round 2 – Question 1Round 2 – Question 1

Excluding AB, crystal faces will most likely occur along whichlattice plane?

ACAC

Round 2 – Question 2Round 2 – Question 2

What does Steno’s Law of Interfacial What does Steno’s Law of Interfacial Angles state?Angles state?

For a particular mineral, the angle For a particular mineral, the angle between adjacent faces will be between adjacent faces will be constantconstant regardless of crystal shape regardless of crystal shape or size.or size.

Round 2 – Question 3Round 2 – Question 3

What does the crystal growth illustration to the left indicate?

a) lattice plane a has a higher atomic density than o,

b) Lattice plane o has a higher growth rate than a, or

c) 111 faces are only common in large, mature crystals

Round 2 – Question 4Round 2 – Question 4

The crystallographic axes shown below are indicative of what crystal system?

HexagonalHexagonal

Round 2 – Question 5Round 2 – Question 5

How are crystallographic axes different between the orthorhombic and tetragonal systems?

The a and b axes in the tetragonal The a and b axes in the tetragonal system are the same length, but system are the same length, but are different in orthorhombic are different in orthorhombic crystals.crystals.

Round 2 – Question 6Round 2 – Question 6

What crystal face would qualify as the “unit face” in this orthorhombic crystal? (give face intercepts)

1a: 1b: 1c1a: 1b: 1c

Round 2 – Question 7Round 2 – Question 7

What is the Miller Index for the upper face?

(113)(113)

Round 2 – Question 8Round 2 – Question 8

What is the Miller index of the shaded face in this hexagonal crystal?

(1120)(1120)

Round 2 – Question 9Round 2 – Question 9

Faces b, m, and a belong to what zone?

[001][001]

Round 2 – Question 10Round 2 – Question 10

What is the form index of the p face?

{111}