MINERALOGY BASIC CONCEPTS (POINT GROUPS AND SYMMETRY NOTATIONS)

Question 1

used to refer to symmetry opreations

Answer 1

Symmetry Symbol

Question 2

this symbol system takes cognizance of the fact that the symmetry elements in a minerals must be related to each other and that some operations are already implied by the presence of others, and therefore need not to be explicitly listed

Answer 2

Hermann-Mauguin

Question 3

In 2D what are the possible symmetry elements?

Answer 3

Rotation and Mirrors

Question 4

What are the crystal classes of the Isometric Crystal System (5)?

Answer 4

Hexoctahedral

Question 5

What are the cystal classes of the Tetragonal Cyrstal system (7)?

Answer 5

Ditetragonal-dipyramidal

Question 6

Crystal Classes under Hexagonal Crystal System (7)

Answer 6

Dihexagonal-dipyramidal

Question 7

Cyrstal Classes under Rhombohedral or Trigonal (Hexgonal) (5)

Answer 7

Hexagonal-Scalenohedral

Question 8

Crystal Classes under Orthorhombic (3)

Answer 8

Rhombic-dipyramidal

Question 9

Cyrstal Classes under Monoclinic

Answer 9

Prismatic

Question 10

Crystal Classes under Triclinic

Answer 10

Pinacoidal

Question 11

Common symmetry elements for triclinic crystal systems?

Answer 11

1pc - One fold rotation w/ or w/o rotoinversion

Question 12

Common Symmetry elements for Monoclinic?

Answer 12

1pc - 2 fold rotation and/or
1pc - single mirror

Question 13

Common Symmetry elements for orthorhombic

Answer 13

3pcs - 2 fold rotation axes and/or
3pcs - mirrors

Question 14

Common Symmetry Elements for Tetragonal?

Answer 14

1pc - 4-fold rotation or rotinversion axes

Question 15

Common symmetry elements for trigonal?

Answer 15

1pc - 3 fold axis

Question 16

Common symmetry elements for hexagonal?

Answer 16

1pc - 6 fold axis

Question 17

Common Symmetry elements for isometric?

Answer 17

4pc - 3 fold axes

Question 18

Who first observed that the angles between crystals are remarkably consistent?

Answer 18

Nicolas Steno (Niels Stensen), 1669

Question 19

What mineral did Nicolas Steno used for his experiment?

Answer 19

Quartz

Question 20

This law states that the angle between equivalent faces on crystals of the same minerals are the same

Answer 20

Law of Constancy of Interfacial Angles

Question 21

This instrument measures crystal angles with reasonable accuracy

Answer 21

Contact Goniometer

Question 22

Theory of Rational Indences for Crystal Faces

Answer 22

Rene J. Hauy

Question 23

Reflecting Goniometer

Answer 23

Wollaston

Question 24

Chemical Classification of Minerals

Answer 24

Berzelius

Question 25

Immersion Method

Answer 25

Cordier

Question 26

Polarizing Microscope

Answer 26

William Nicol